Terminology
Watchmaking vocabulary written for authentication: what the term means, and what its presence or absence tells an examiner.
Authentication practice
COSC chronometer certification
Certification by the Contrôle Officiel Suisse des Chronomètres, testing an uncased movement over fifteen days in five positions and three temperatures to a mean daily rate of −4 to +6 seconds.
Why it matters in examination
'Chronometer' on a dial is a specification claim tied to a certified movement, checkable against the caliber record. It is distinct from house standards such as Rolex's Superlative Chronometer or Grand Seiko's internal grades, which are applied on top of or instead of COSC and are frequently conflated with it in listings.
Related terms Master Chronometer
Correctness classification
The scheme distinguishing factory-original, period-correct, service-correct, aftermarket and counterfeit components, with 'unknown' as a first-class answer.
Why it matters in examination
The central discipline of component-level examination. Collapsing these into authentic/fake is the error that produces both false condemnations of serviced watches and false confidence in assembled ones. Only 'counterfeit' is a finding against authenticity; the rest concern originality and value.
Related terms Service dial · Marriage · Period correct
DIVER'S marking
ISO 6425 · Diver's 200mThe apostrophe-form dial marking indicating a watch built and tested to ISO 6425, which requires more than a pressure rating: legibility in darkness at a defined distance, a pre-set time indicator, and resistance to shock, magnetism, salt water and external force on the crown.
Why it matters in examination
This distinguishes an SKX007 ('DIVER'S 200m', ISO certified) from a 5 Sports SRPD (100m, not certified) despite their near-identical cases. A specification report should transcribe the dial marking exactly rather than paraphrasing it as 'dive watch'.
Related terms Movement-case number
Display piece that became a product
A watch originally built for retail demonstration rather than sale — typically with parts omitted to expose the mechanism — which the manufacturer subsequently catalogued as a saleable model because customers wanted it.
Why it matters in examination
Creates a specific and awkward authentication problem, of which the Bulova Accutron Spaceview is the defining example. Because the display configuration is defined by what has been LEFT OUT, an ordinary example can be converted into the valuable one by removing the same part — the dial — using nothing but genuine components. Such a watch is authentic in every part and misdescribed as a whole, so the correct finding is MODIFIED rather than counterfeit, and the test is documentary rather than physical: does this model appear in the period catalogues as a factory display model? Nothing on the watch itself can answer it.
Related terms Value concentrated in a single component · Correctness classification
Franken watch
A watch assembled from parts of several watches and of several periods, generally to present as a more valuable configuration than any of its sources.
Why it matters in examination
Differs from a marriage in degree and in intent. Identified by internal inconsistency across components rather than by any single part — which is why component-level records with period windows are more useful here than any list of red flags.
Related terms Marriage · Correctness classification
Frankenwatch
Composite watch · Parts watchA watch assembled from parts of several watches, or from a mixture of original, service and aftermarket components, and presented as a single original watch.
Why it matters in examination
The dominant integrity problem on vintage Seiko, and one where every individual part may be genuine. Complete counterfeits are comparatively rare; composites are everywhere, because parts are plentiful and interchange freely across generations. The check is not part-by-part genuineness but consistency — dial, hands, bezel, crown, case and movement should agree about the watch's age, wear and service history. Describing a composite as a fake is inaccurate; describing it as original is the actual misrepresentation.
Related terms Proof and Resist · LumiBrite
Generational redesign
A comprehensive revision of a long-running model in which many details change at once — case proportions, bezel treatment, dial markers, caseback and movement — while the design remains recognisably the same watch.
Why it matters in examination
The characteristic way a well-informed examiner reaches a wrong conclusion. Detail checks learned on one generation will fail a correct example of the other, and because the model looks the same, nothing prompts the examiner to ask which generation they are holding. The Chanel J12's 2019 revision is the clearest case in this catalog — it changed the movement as well as the details — and the same hazard attaches to any long-running reference. The rule is procedural: establish the generation from the reference FIRST, then select the checks. A detail finding without a generation is not a finding.
Related terms Functional complication test · Correctness classification
Geneva Seal
Poinçon de GenèveA certification administered by the Canton of Geneva for movements finished and assembled there to a defined construction and finishing standard. Since 2011 its criteria extend to the assembled watch and include timekeeping and water-resistance testing.
Why it matters in examination
An origin and finishing certification, not a precision one and not a quality ranking — which is how it differs from COSC and Master Chronometer, and why placing the three on a single scale is a category error. Its absence establishes nothing: a great many excellent movements are made outside Geneva and are ineligible by geography. Where it is most useful is chronological, because manufacturers have adopted and abandoned it: Patek Philippe replaced it with its own Seal in 2009, so on a Patek the two marks are a dating boundary and each is an anachronism on the wrong side of it.
Related terms COSC chronometer certification · Master Chronometer · Côtes de Genève
Interchangeable-parts brand
A manufacturer whose watches are built from a pool of freely combinable components, sold and serviced that way, so that no single configuration is canonical. Vostok is the clearest example in this catalog.
Why it matters in examination
Changes what the correctness vocabulary means. On such a brand, a part that is not original to the watch is the normal condition of a genuine example, and classifying it as a marriage would misdescribe the object — the catalog uses `period` and `unknown` where it would otherwise use `factory`. The examination answers what the watch is made of and whether it works, not whether it is untouched. Applying prestige-brand originality standards here would condemn the majority of authentic watches.
Related terms Marriage · Franken watch · Correctness classification · Period correct
Laser-etched crown (LEC)
A microscopic coronet etched into the sapphire crystal at 6 o'clock, introduced across the range in the early 2000s.
Why it matters in examination
Routinely described as a test and it is not one. Counterfeiters reproduce it convincingly at the magnification most examiners use, it postdates the early 2000s so its absence on older watches is expected, and it lives in a crystal that gets replaced at service. A crude or obtrusive etching is a real finding — against the crystal, which is a much weaker claim than against the watch.
Related terms Rehaut · Crystal · Cyclops lens
Marking that asserts a construction
A stamped or engraved mark that certifies how a watch is built rather than who built it — Certina's DS turtle, a depth rating, a chronometer designation — and which therefore makes a claim the rest of the watch can support or contradict.
Why it matters in examination
Turns a marking from something to be compared into something to be TESTED, which is a considerably stronger position. An engraving can be reproduced by anyone with a laser; the construction it claims — a shock-mounted movement, a crystal of a given thickness, a case that actually holds its rated depth — cannot be reproduced cheaply. So the correct response to such a marking is to look for the construction rather than to examine the marking. Two cautions apply generally: these markings usually have a start date, so their absence on an early example may be correct; and they are typically on a caseback, so a marking contradicted by the watch implicates the caseback first.
Related terms Testable material claim · Government specification as identifier
Marriage
A watch assembled from genuine parts that never left the factory together — most often a correct movement in a case from a different watch.
Why it matters in examination
The hardest common problem in vintage authentication, because every individual part passes examination. Detection depends on relationships rather than parts: case and movement numbers that do not correspond in the archive, a caliber outside the reference's documented window, a configuration no documented production run produced. This is precisely what a fitment graph exists to make checkable.
Related terms Correctness classification · Franken watch
Master Chronometer
Certification administered by METAS, the Swiss federal metrology institute, testing the cased watch across eight criteria including exposure to a 15,000 gauss magnetic field.
Why it matters in examination
A materially stronger claim than COSC because it tests the assembled watch and is administered independently of the manufacturer. Its presence on a dial dates a watch to 2015 or later.
Related terms COSC chronometer certification
Period correct
A component consistent with the watch's production era and reference, but not demonstrably original to that particular watch.
Why it matters in examination
The honest classification for most parts on most vintage watches, where originality cannot be proven either way. It is a positive finding, not a hedge.
Related terms Correctness classification
Strap as primary evidence
An examination approach in which the strap, rather than the case, dial or movement, is the first and strongest evidence — appropriate where the manufacturer's core competence is leatherwork and the strap is made to a standard the watch industry does not generally reach.
Why it matters in examination
Applies principally to Hermès, and inverts the normal order of examination for a good structural reason: a counterfeiter who has solved case machining and dial printing has solved watchmaking problems, and fine leatherwork is a different trade requiring different skills, tooling and materials. Stitch pitch and regularity, edge finishing that is burnished rather than sprayed, the hand and smell of the leather, and the stamped markings are all judgeable without opening the watch. The necessary caution runs the other way: straps are consumables, genuine watches are routinely re-strapped with aftermarket leather, and a non-Hermès strap on a genuine Hermès watch is an originality note and nothing more. The strap can convict a counterfeit; it cannot condemn a re-strapped genuine watch.
Related terms Geometry as identity · Correctness classification
Testable specification
A published performance claim — power reserve, water resistance, magnetic resistance, accuracy — that can be verified by operating the watch rather than by inspecting it.
Why it matters in examination
Shifts authentication from appearance to behaviour, which is the stronger ground wherever it is available, because a counterfeit can be made to look right far more cheaply than it can be made to perform right. The Baume & Mercier Baumatic's 120-hour reserve is the clearest example in this expansion: wind it fully, leave it, and see whether it runs on the fifth day. A conventional automatic will have stopped after two. The test's slowness is not a weakness — it requires no expertise and no equipment, which means it can be run by an owner rather than an examiner. The same reasoning covers depth ratings, magnetic resistance and chronometer accuracy.
Related terms Observatory certification · Functional complication test
Value concentrated in a single component
A configuration in which almost all of a watch's value differential over its siblings resides in one replaceable part — typically a dial — while its case and movement are shared with far cheaper references.
Why it matters in examination
Determines where the fraud will be, and therefore where the examination should start. On the Universal Genève Nina Rindt, the Rolex 'exotic' dial Daytonas, and elsewhere in this catalog, the profitable alteration is not to counterfeit a watch but to fit the valuable component to a genuine, cheaper one. Such a watch is genuine in every part but one, and every conventional check on case, movement, hands and caseback will pass. The correct response is to invert the usual order: assume the rest of the watch is real, treat the value-bearing component as the object of the examination, and rely on CONSISTENCY between components — matching lume colour, matching wear, matching age — rather than on any component judged alone.
Related terms Brand without a surviving archive · Redial
Bracelets & clasps
End link
The fitted piece joining a bracelet to the case between the lugs, shaped to the specific case it serves and identified by its own code.
Why it matters in examination
End links are reference-specific. A wrong end link produces visible gapping and is a genuine fitment finding — about the bracelet, and therefore about originality rather than authenticity, unless other evidence points further.
Related terms Lug width · Folded link
Folded link
A bracelet link formed by folding sheet metal rather than machining it from solid, standard on Oyster bracelets into the 1970s.
Why it matters in examination
Folded links are light and develop stretch with wear — expected condition on a period bracelet, not a defect and not a sign of a copy. Solid links on a reference documented with folded ones indicate a later or replacement bracelet.
Related terms End link · Solid end link (SEL)
Solid end link (SEL)
A machined end link, replacing the earlier folded construction and giving a tighter fit against the case.
Why it matters in examination
The change from hollow to solid end links is a dating boundary within several sports references, and a useful check on whether a bracelet belongs to the period of the case it is on.
Related terms End link · Folded link
Case construction
Articulated lugs
Lugs mounted on pivots so they move relative to the case body, allowing the watch to conform to the wrist — a mechanical assembly rather than a case shape.
Why it matters in examination
A near-binary check, and one of very few in this catalog that can be performed in a second with no equipment: the lugs either pivot or they do not. Reproducing the LOOK of articulation costs a counterfeiter nothing, and reproducing a working pivot with correct tolerances and controlled resistance costs a great deal, so this is exactly the kind of feature that separates a copy from the object. The necessary caution runs the other way: a moving assembly wears, and excessive play in the lugs of a genuine used watch is a service finding rather than an authenticity one. It is the presence of a functioning mechanism that matters, not its tightness.
Related terms Thermal blueing · Low-volume manufacturer confirmation
Bezel-locking mechanism
A mechanical device that physically prevents a rotating dive bezel from turning until released — a hinged clamp, a screw-down ring, or a sprung catch — as distinct from the friction detent that holds an ordinary dive bezel.
Why it matters in examination
Directly testable, which makes it a stronger check than almost any visual feature: engage the lock and try to turn the bezel. On the Yema Superman, which has carried a hinged locking bridge since 1963, a bezel that rotates with the lock engaged means a replaced bezel, a worn mechanism, or a copy that reproduced the appearance without the function. The important limitation is that a working mechanism does NOT establish period where the manufacturer's modern reissues reproduce it faithfully — the test confirms the model, and the crystal, case finishing and movement establish the era.
Related terms Functional complication test · No-decompression bezel
Compound curvature
A case curved in two planes simultaneously — along its length and across its width — requiring the crystal, dial and movement mounting to follow the same double curve.
Why it matters in examination
One of the most cost-effective checks in this catalog, because it exploits a manufacturing expense rather than an appearance. A doubly curved sapphire crystal is genuinely expensive to produce and a counterfeiter's economics do not support one, so copies use a single-plane case with a flat or nearly flat crystal. The crucial practical point is the VIEWING ANGLE: from directly above — the angle of almost every listing photograph — a single-plane copy looks correct, and from the side it does not. Asking a seller for a profile view is therefore the highest-yield question available on any compound-curved watch, and it costs nothing. One caution: a genuine case may have been fitted with a generic crystal at service, so establish whether the CASE curves in both planes before condemning the watch on the crystal.
Related terms Drawn numerals · Geometry as identity
Compression-principle case (Amphibia)
A water-resistant case design in which a thick domed acrylic crystal deforms under external pressure and presses harder into its seat, so the seal improves with depth rather than resisting it. Developed at the Chistopol factory because conventional 200m case tolerances were beyond its manufacturing.
Why it matters in examination
Two practical consequences. A sapphire replacement crystal cannot deform and therefore defeats the principle, so a sapphire-fitted Amphibia should not be assumed to hold its rated depth — a functional finding rather than an originality one. And the crown's free play when unscrewed is correct by design; reporting it as a defect is the standard first-time error on the brand.
Related terms Water resistance · Crystal · Screw-down crown
Cork crown seal
A crown sealing system using a cork element that swells slightly on contact with water, tightening the seal in use. Mido's Aquadura is the principal example.
Why it matters in examination
Produces a failure mode that looks like a false specification and is not one. Cork dries and shrinks when a watch is stored unworn for years, so a period watch with this system will frequently fail a pressure test while its original specification was entirely genuine. The correct report is a service condition. There is a secondary originality point: where the cork component was unavailable, watchmakers have long substituted conventional gasketed crowns, so a working period Mido may no longer carry the system it is known for — a service finding worth recording rather than passing over.
Related terms Monobloc case
Crown-protecting bridge
Luminor bridge · Crown guard leverThe hinged bridge and clamping lever over the crown of a Luminor, which compresses the crown against its gasket when closed. It is what distinguishes a Luminor case from a Radiomir.
Why it matters in examination
A mechanism rather than a shape, so it is tested by feel: the lever should close with firm resistance and visibly clamp. A counterfeit case can reproduce the appearance far more easily than the tolerances, which makes the action a better check than the look.
Related terms Screw-down crown · Water resistance
Crystal
The transparent cover over the dial, in acrylic (Hesalite, Plexiglas), mineral glass or synthetic sapphire.
Why it matters in examination
Crystal material is a reference specification and is among the most commonly replaced parts. A sapphire crystal on a reference specified with acrylic is a configuration difference to record — usually service or aftermarket, occasionally a variant of the reference itself.
Related terms Cyclops lens · Hesalite
Cyclops lens
A magnifying lens fused over the date aperture on the crystal, magnifying the date roughly two and a half times on Rolex watches.
Why it matters in examination
Magnification factor, the date's centring within the lens, and the lens's own edge finishing are all commonly examined. Frequently under-magnified on counterfeits — a supporting indicator, and one that a replacement crystal on a genuine watch can also fail.
Related terms Crystal
Destro (left-hand crown)
A crown positioned at 9 o'clock so the watch can be worn with the crown away from the back of the hand.
Why it matters in examination
Distinguish two causes that look identical. On a Heuer Caliber 11 the left crown is a CONSEQUENCE of the movement's module occupying the stem position, so it is a caliber check. On a destro diver such as the JB200 it is a design decision with a conventional movement rotated in the case, so it says nothing about what is inside. Reading one as the other produces a confident wrong conclusion in either direction.
Related terms Module · Screw-down crown
Geometry as identity
A design whose identity resides in fixed proportional relationships — the ratio of a case rectangle to its inner dial square, the relative lengths of asymmetric lugs, the stroke widths of a case formed as a letter — rather than in applied decoration.
Why it matters in examination
Turns authentication into measurement, which is the most reliable form it can take. A motif can be copied by anyone with a photograph; a proportion has to be tooled, and counterfeiters reproduce the IDEA of a shape while getting its ratios wrong. It applies across Hermès — the Arceau's stirrup lugs, the Cape Cod's chain-link rectangle, the Heure H's letterform — and equally to any design built on a specific geometry. The practical method is to measure against published case dimensions rather than to compare against a remembered image.
Related terms Strap as primary evidence · Testable material claim
Government specification as identifier
A military or government procurement specification number — GG-W-113, MIL-W-46374, W10, NATO stock numbers — stamped on a watch to record the standard it was built to rather than the model the manufacturer sold.
Why it matters in examination
Three consequences. It is not a manufacturer reference, so looking it up in a brand catalog finds nothing. It is multi-contractor, so it identifies the standard and not the maker — the movement identifies the maker. And it lives on a caseback that unscrews, which makes it simultaneously the most valuable and the most portable part of the watch's identity, so a correct specification caseback on the wrong watch is the single most common construction in issued-watch collecting.
Related terms Movement grade as product identity · Correctness classification
Helium escape valve
HEV · helium release valveA one-way valve that vents helium which has permeated a watch case during saturation diving, preventing internal pressure from displacing the crystal during decompression. Fitted at 10 o'clock on the Omega Seamaster Diver 300M and Planet Ocean.
Why it matters in examination
Relevant to construction rather than to diving: the valve boss is part of the case, so its presence, absence, alignment and finish are checkable case facts. A Diver 300M case with no valve boss is not that model. Two further points that generalise beyond Omega. It is a real mechanical fitting with a mechanism behind it, and counterfeits and lesser homages reproduce a valve-shaped protrusion with nothing behind it — so the check is whether a mechanism EXISTS, not whether a shape does. And because the valve solves a problem confined to saturation diving, its presence on any watch outside that context is a claim about lineage rather than capability, which is worth stating plainly when advising an owner. The priority question is settled once the claims are stated precisely, and both brands are right about different things: Rolex filed the patent (Swiss CH 492 246, 6 November 1967) and fitted a valve to the Sea-Dweller from 1967, but supplied those watches to commercial diving contractors rather than the public, while Doxa's 1969 SUB 300T Conquistador was the first a member of the public could buy. The concept itself came from US Navy SEALAB diver Robert A. Barth, who brought it to Rolex. Report the distinction rather than either unqualified claim.
Related terms Water resistance · Screw-down crown · No-decompression bezel
Hippocampus (Seamaster seahorse)
Seahorse medallion · Seamaster medallionThe seahorse emblem carried on Seamaster casebacks since the 1950s, executed as a stamped relief on vintage backs and as a defined medallion on modern ones.
Why it matters in examination
Asymmetric evidence, and the asymmetry is the whole point. A shallow, soft or misproportioned hippocampus is a strong counterfeit indicator because the relief is difficult to reproduce. A well-executed one proves only that the caseback is genuine — and casebacks are separable, replaced at service, and swapped between watches.
Related terms Marriage · Service dial
Jumbo (Royal Oak Extra-Thin)
Collector and, latterly, manufacturer shorthand for the extra-thin 39mm Royal Oak descending from the 1972 reference 5402 — the 15202 and now the 16202. The name records that the original was large for its day, which it no longer is.
Why it matters in examination
The thinness is the point, and it constrains the movement: a Jumbo case takes an extra-thin caliber, historically the Jaeger-LeCoultre 920 architecture and now the 7121. A thicker automatic in a Jumbo case is a physical contradiction rather than a variant.
Related terms In-house movement · Ébauche
Layered (sandwich) case construction
A case assembled as a screwed stack of bezel, gasket, body and back, with the construction and its fasteners visible from outside rather than concealed.
Why it matters in examination
Puts the tolerances on display. Layer alignment, gasket compression and the meeting of brushed and polished surfaces across different materials can all be judged without opening the watch — and the finishing is harder than it appears, because ceramic, titanium and steel take it differently. On the Big Bang the six H-headed bezel screws should all read the same way round; alignment is the manufacturing discipline a counterfeit fails, not the head shape.
Related terms Correctness classification · Water resistance
Left-hand crown (Caliber 11 family)
The crown position on watches carrying the 1969 Chronomatic calibers 11, 12 and 15, in which a chronograph module sits over a micro-rotor base and occupies the space the winding stem would otherwise use.
Why it matters in examination
A mechanical consequence rather than a styling choice, which makes crown position a caliber-family check performed by looking at the case — no magnification, no disassembly. A watch presented as a Caliber 11-era Monaco or Autavia with a right-hand crown warrants establishing what is actually inside it. Note it identifies the family and not the individual caliber: the 11, 12 and 15 all place the crown left.
Related terms Module · Integrated chronograph
Lug width
The gap between the lugs, which fixes the strap or bracelet width the case accepts.
Why it matters in examination
Determines which bracelets and end links can legitimately be fitted. A bracelet of the wrong width is a fitment finding that requires no expertise to observe.
Related terms End link · Lug-to-lug
Lug-to-lug
The distance from the outer tip of one lug to the outer tip of the opposite lug — the measurement that actually determines how a watch sits on a wrist.
Why it matters in examination
Case dimensions are among the harder things to reproduce exactly, and lug-to-lug is less often quoted in listings than diameter, which makes it a useful independent check against a documented specification.
Related terms Lug width
Monobloc case
A case formed as a single component with no separable caseback, the movement being installed and serviced through the front under the crystal.
Why it matters in examination
Inverts a default expectation. An examiner looking for a screw-down caseback on a monobloc watch will not find one, and its absence is the specification rather than a fault or a sign of tampering — while its PRESENCE on a reference specified as monobloc indicates a counterfeit built on a conventional case. It also has a practical consequence: the caseback engravings that normally carry the reference and serial are somewhere else, and a service requires removing the crystal, so crystal-seal condition rather than caseback-gasket condition is what tells you about the watch's service history.
Related terms Hardness versus toughness
Nautilus two-part case
The Nautilus construction in which the case is built in two parts joined at the sides by projecting 'ears', with the bezel clamped to the case body rather than a back screwed or snapped into it. Derived from a ship's porthole.
Why it matters in examination
A manufacturing problem rather than a shape, which is what makes it useful: the bezel-to-case joint must be a fine even line all the way round, and the ears must be integral to the case profile and finished continuously with it. Along with the bezel chamfer, this is where counterfeits of the model fail — the cost of getting it right is hand labour, which a fake cannot cheaply buy.
Related terms Correctness classification · Anglage
No-decompression bezel
A rotating dive bezel carrying no-decompression limits — maximum bottom time against depth — rather than a plain sixty-minute elapsed-time scale, making the bezel a calculating instrument.
Why it matters in examination
Unusually checkable, because it reproduces a published external standard. The figures on the insert either correspond to a real diving table of the watch's period or they do not, which allows a component to be verified against a document rather than against other watches — something this catalog can rarely do. The countervailing fact is that inserts are consumables: they fade, they are damaged, and they are replaced with service parts and reproductions alike, so a crisp insert on a worn case is a restoration finding rather than evidence against the watch.
Related terms Dial colour as model identity · Helium escape valve
Rehaut
flange · inner bezelThe inner flange between the dial edge and the crystal, sometimes carrying a minute track and, on modern Rolex watches, an engraved serial and repeating brand text.
Why it matters in examination
Engraving quality and alignment to the hour markers are checkable with a loupe and are a common examination point. Reproduction has improved markedly, so treat alignment as supporting evidence rather than a test — and note that a service dial can shift alignment on a genuine watch.
Related terms Serial number
Reverso carrier and cradle
The two-part Reverso case: a carrier fixed to the strap and a case body that slides within it and pivots through 180 degrees, designed in 1931 to protect the crystal during polo.
Why it matters in examination
A mechanism with tolerances rather than a decorative hinge, which makes it testable in seconds and without tools — slide, pivot through a full half turn, confirm it locks with no lateral play. That is where reproductions fail, because the action needs machining rather than a shape. Wear on an old example produces play and is a condition observation, not a finding; it does remove the check.
Related terms Correctness classification
Sapphire sandwich
Collector shorthand for a Speedmaster Professional catalogued with a sapphire crystal and a sapphire display caseback, as distinct from the Hesalite-and-solid-back execution.
Why it matters in examination
Prevents the most common false finding on the model. Sapphire on a Speedmaster is not automatically incorrect: the question is which execution the REFERENCE was, and a sapphire crystal is original on some references and a substitution on others. Establish the reference before judging the crystal.
Screw-down crown
A crown that threads onto a tube fixed in the case, compressing gaskets to seal the winding stem aperture.
Why it matters in examination
Rolex codes its crown generations with dots and bars beneath the coronet — Twinlock and Triplock — so the crown face states which system the case uses and can be checked against the reference.
Related terms Water resistance
Soft-iron inner cage
Faraday cage · antimagnetic inner caseAn inner case of soft iron surrounding the movement, which conducts magnetic flux around it rather than through it. Used by IWC on the Mark series and Big Pilot, and by Rolex on the Milgauss.
Why it matters in examination
A case property, not a movement one — the caliber inside is ordinary. Two consequences follow. The cage must be closed to work, so a display caseback and a soft-iron cage are mutually exclusive and a reference claiming both is contradictory. And a watch that has lost its cage has lost the property the model exists for, which is invisible from the outside and worth reporting when the movement is out.
Related terms Correctness classification
Triplock and Twinlock crowns
Rolex's two screw-down crown systems, with three and two sealing gaskets respectively. The crown's dial-side face carries dots or a line beneath the coronet indicating which system and which case metal.
Why it matters in examination
The marking under the coronet is reference-specific, so a crown whose marking does not match the reference is a real observation — and it is an observation about the CROWN, which is among the most frequently replaced parts on any Oyster. Read it as a fitment question before an authenticity one. The gasket count also matters practically: a Triplock reference fitted with a Twinlock crown is not sealed to its rated depth.
Related terms Screw-down crown · Water resistance · End link
Tsunami medallion
Wave medallionThe stamped wave relief on the casebacks of Seiko dive watches, used from the 6105 era onward.
Why it matters in examination
A line marker rather than a certification. It is reproduced on counterfeit casebacks and appears on genuine casebacks fitted to the wrong watch, so its presence establishes little; its absence on a dive reference is worth a question.
Related terms Movement-case number
Water resistance
A rating, expressed in metres or atmospheres, from a static pressure test to a defined standard. It is not a diving depth.
Why it matters in examination
The rating is a specification of the watch as manufactured, checkable against the reference record. It says nothing about the watch in front of you: gaskets perish, and a rating is meaningless after decades without a pressure test.
Related terms Screw-down crown
Complications
Annual calendar
A calendar that distinguishes 30- and 31-day months mechanically and therefore requires correction only once a year, at the end of February. Patented by Patek Philippe in 1996.
Why it matters in examination
Routinely conflated with a complete calendar in listings and even in condition reports, and the distinction is testable: a complete calendar needs correcting at the end of every short month, an annual calendar does not, and a perpetual calendar does not need correcting at all until 2100. Establishing which complication is actually present settles what the watch is before any question about whether it is genuine.
Related terms Module · Integrated chronograph
Cam switching (shuttle)
shuttle · cam-actuated chronographA chronograph switching system using a cam and levers in place of a column wheel. Simpler to manufacture and to service, and mechanically sound.
Why it matters in examination
Frequently misrepresented as an inferior or later cost-cut. It is neither — but it does date and identify a caliber, which is the useful part.
Related terms Column wheel
Column wheel
A toothed, pillared wheel that sequences the start, stop and reset functions of a chronograph by rotating a fraction of a turn with each press.
Why it matters in examination
Column-wheel versus cam switching is often the decisive distinction between two calibers that are otherwise similar — the Omega 321 and 861 being the standard example. Visible with the caseback off, and a reliable caliber-identification check.
Related terms Cam switching (shuttle) · Integrated chronograph
Functional complication test
Authenticating a watch by operating its complication and observing whether it behaves as the mechanism requires — a jumping hour that jumps instantaneously, a retrograde hand that flies back, a chronograph that resets to zero without creep.
Why it matters in examination
Among the strongest evidence available, because a complication is a mechanism rather than an appearance and a movement that lacks the mechanism cannot imitate the behaviour. A conventional hour hand behind an aperture creeps round over the hour where a true jumping hour changes in an instant; the difference takes minutes to observe and no equipment at all. It applies wherever a watch's identity rests on a demanding complication — Chanel's Calibre 1, and every jumping-hour, retrograde and rattrapante elsewhere in the catalog. The caveat is that the watch must be running and correctly set, and that a genuine watch in need of service may fail the test for reasons that say nothing about its authenticity.
Related terms Tuning-fork movement · Correctness classification
Integrated chronograph
A chronograph whose timing mechanism is designed into the movement rather than added as a module, sharing plates and bridges with the base.
Why it matters in examination
Integrated and modular chronographs look different through a display back and have different heights. Establishing which one a caliber is narrows the identification considerably before any finishing is examined.
Related terms Module · Column wheel · Vertical clutch
Integrated versus modular complication
Whether a complication is designed into the movement's own architecture or added as a separate module mounted above a base caliber — a chronograph module on a time-only base, a calendar plate above an automatic.
Why it matters in examination
A large price difference and a visible structural one, which makes it a description check rather than an authenticity check in most cases. Through a display back an integrated complication reads as part of the movement, while a module sits above a recognisable base as a separate plate carrying its own works. Both are legitimate; only one is what a manufacture claim implies. It also has service consequences worth recording: modules are generally easier and cheaper to service than integrated works, and a module can usually be identified by the base movement remaining visible beneath it.
Related terms Functional complication test · Two manufactures under one brand
Moonphase precision gearing
The tooth count of the wheel driving a moonphase disc, which determines how closely the display approximates the synodic month and therefore how quickly it drifts. A conventional 59-tooth arrangement drifts about a day every two and a half years; high-precision trains use much larger counts and drift by a day only after centuries.
Why it matters in examination
One of very few marketing claims in watchmaking that is arithmetic rather than rhetorical. An accuracy quoted in hundreds of years follows necessarily from a specific gear ratio, so the claim can in principle be verified by counting teeth through a display back — laborious, and conclusive. More practically, it means the claim is falsifiable: a watch advertising centuries of accuracy while driving its moon from a standard 59-tooth wheel is making a statement that its own gearing contradicts.
Related terms Dial-side architecture · Testable specification
Multi-axis and inclined tourbillon
A tourbillon whose carriage is inclined out of the dial plane, nested inside a second carriage rotating on a different axis, or both — addressing the fact that a conventional single-axis tourbillon averages positional error only within its own plane.
Why it matters in examination
One of the more decisive checks in this catalog, because it is a three-dimensional moving mechanism rather than an appearance. Watch it: the rotations must be present, at their stated rates, in their stated planes. Where the rotation period is published — Greubel Forsey's twenty-four-second carriage against the conventional sixty — the claim can be TIMED with nothing but a second hand, which is about as direct as verification gets. The general caution about tourbillons applies with force at the cheaper end of the market: a rotating disc in a dial aperture is not a tourbillon, and the distinction is between a carriage that carries an oscillating balance around with it and a decorative element turning behind an opening.
Related terms Anglage · Black polishing · Functional complication test
Perpetual versus annual calendar
A perpetual calendar accounts for both 30-day months and leap years and needs no correction until 2100; an annual calendar handles 30-day months but must be corrected each February; a simple calendar handles neither.
Why it matters in examination
The distinction is worth several times the price of the watch and can be settled in minutes, because the calendar can be advanced by hand. Wind past the end of a 30-day month: a perpetual steps to the 1st, a simple calendar shows a 31st. Wind past February: an annual calendar fails where a perpetual does not. Check that the leap-year indicator, where one exists, advances in step with the years. This is among the most decisive functional tests in the catalog and it requires nothing but the watch and patience with the crown.
Related terms Integrated versus modular complication · Functional complication test
Vertical clutch
A chronograph coupling in which friction discs engage vertically, rather than a lateral clutch swinging a wheel into mesh.
Why it matters in examination
A vertical clutch eliminates the small jump of the chronograph seconds hand on starting that a lateral clutch produces. Observable while the watch runs, without opening it.
Related terms Integrated chronograph
Wandering hours
A time display in which hour numerals ride on satellites mounted to a rotating carrier, each numeral travelling along a minute track to indicate the time by its position before giving way to the next. Used in seventeenth-century night clocks and revived by Urwerk as a wristwatch complication.
Why it matters in examination
Close to an ideal authentication subject, because the complication is simultaneously the watch's only visible feature and a mechanism that must behave correctly over time. Two conditions have to hold and both are observable: the active numeral must read the CORRECT minute against the scale throughout its arc, and the changeover to the next satellite must occur at the hour. A copy reproducing the appearance without the gearing drifts against the scale, indexes at the wrong moment, or rotates at a constant rate — all visible within an hour. Distinguish that from wear: a used mechanism may wobble or index hesitantly while still telling the right time, which is a service finding rather than an authenticity one.
Related terms Functional complication test · Dial-side architecture
Winding-efficiency indicator
A display reporting how much energy a watch's automatic winding system has actually delivered over a recent period, as distinct from a power-reserve indicator showing how much energy remains.
Why it matters in examination
Unusually resistant to imitation, because the indication CHANGES with how the watch has been worn. A power reserve can be mimicked by a hand that moves with the mainspring; an efficiency indicator has to respond to the wearer's activity, so it should read differently after an active period than after the watch has sat still. That makes it a test conducted over hours rather than seconds, and one that a static or decorative indicator fails absolutely. Where a watch offers a display of its own operating behaviour, wearing it is the examination.
Related terms Wandering hours · Testable specification
Dial & hands
Commissioned typography
Numerals or lettering drawn specifically for one watch by a named typographer, existing on no other object and available from no type library.
Why it matters in examination
An unusually strong dial check, because it denies the copyist a source. Where a dial uses a commercially available typeface, a counterfeiter can obtain the exact letterforms and reproduce them perfectly; where the type was commissioned — as with Philippe Apeloig's numerals for the Slim d'Hermès — they must redraw it by eye from photographs, and redrawn type carries characteristic errors in stroke weight, counter shape and optical spacing that survive at magnification. Compare the letterforms against a documented example rather than reading the text.
Related terms Geometry as identity
Dial code
The code printed at the foot of a vintage Seiko dial, below 6 o'clock, generally comprising a caliber code and a dial variation code and sometimes a trailing supplier letter.
Why it matters in examination
It is normal for a dial code's trailing group to differ from the caseback's — market and day-wheel differences account for much of it — so a mismatch is a question rather than a finding. The supplier-letter attributions rest on collector research rather than Seiko documentation and should not be treated as decisive.
Related terms Movement-case number · Suwa and Daini Seikosha
Dial colour as model identity
A naming convention in which the manufacturer catalogues configurations by dial colour, so that the colour name is part of the model designation rather than a description of a variant — Doxa's Professional, Searambler, Sharkhunter, Divingstar and Caribbean.
Why it matters in examination
Promotes the dial from a component to an identifier. Where colour is the model, a disagreement between the stated name and the dial in front of you is a first-order finding: the watch has been redialled, reassembled from parts, or misdescribed, and which of those has to be resolved before anything else is assessed. It also means a redial on such a brand does not merely reduce originality — it changes what the watch IS.
Related terms Redial · No-decompression bezel
Drawn numerals
Dial numerals created as original artwork with deliberate irregularities of weight, proportion and spacing, rather than set from an available typeface.
Why it matters in examination
Denies a copyist a source, and produces a counterintuitive tell. Where a dial uses a commercial typeface, a counterfeiter can obtain the exact letterforms; where the numerals were drawn — Franck Muller's Art Deco figures, the commissioned Apeloig numerals on the Slim d'Hermès — they must be redrawn by eye from photographs. Redrawing regularises: the copy comes out tidier, more even and more symmetrical than the original. An examiner expecting a counterfeit to look sloppier than the real thing will therefore look straight past the evidence. Compare the numerals as a SET against a documented example, judging relative weight and optical spacing rather than individual character shapes.
Related terms Commissioned typography · Compound curvature
Founding year printed on the dial
A four-digit year printed beneath a brand's wordmark recording when the company was established — 1853 on Tissot, 1888 on Certina, 1875 on Bulova — rather than anything about the individual watch.
Why it matters in examination
Routinely mistaken for a model name or reference number, particularly on Tissot, where a large share of secondary-market listings describe watches as a 'Tissot 1853'. An examiner given that as the model identification has been given nothing. The year does carry one genuine use: because it is the smallest printing on the dial, it is usually the first element to thicken, smear or misalign on a counterfeit, so its EXECUTION is diagnostic even though its content is not.
Related terms Correctness classification
Fumé (gradient) dial
A dial lacquered so that its colour grades continuously from a bright centre to a dark periphery, without visible banding or a discrete transition.
Why it matters in examination
A finishing achievement rather than a printing one, which makes it harder to copy than most dial features and easier to assess than most finishing. The test is optical and needs no equipment: rotate the watch under diffuse light and watch the gradient. A correct one stays even and concentric as the light moves; a copy reveals banding from lacquer applied in discrete passes, pooling, or a bright centre that sits off the dial's axis. Static photographs conceal all three, which is why this check has to be made in motion — and why it should be requested as video rather than stills where the watch is remote.
Related terms Unbranded dial
Maxi dial
Collector shorthand for the later Submariner dials whose luminous markers are visibly larger than the earlier ones, and for the generations of that enlargement.
Why it matters in examination
Collector vocabulary, not Rolex's, and the generations within it are ordered by community research rather than by any published record. Useful for placing a dial relative to others and unreliable for dating one. A maxi dial in an earlier reference is more often a service dial than a fake — which is the reading to reach for first.
Related terms Service dial · Redial · Luminova / Super-LumiNova
Mystery display
A time display in which the indications appear unsupported, achieved by mounting markers or hands on transparent rotating discs rather than on visible arbors.
Why it matters in examination
Shifts the assessment from appearance to behaviour, because the components that matter are the ones designed to be invisible. The discs must rotate concentrically, hold the markers in correct relation, and remain optically clear — and none of that can be judged from a still photograph, which is worth stating explicitly when a watch is being assessed remotely. The corresponding caution is that these mechanisms are delicate, specialist to service and often decades old, so a period example with hazed discs or a wobbling marker is very often a condition problem rather than an authenticity one.
Related terms Corporate discontinuity · Functional complication test
Patina
Age-related change in a dial's or lume's colour and texture — cream and amber tones in aged tritium, tropical browning in some dial lacquers.
Why it matters in examination
Valued by collectors and therefore artificially reproduced. Genuine patina is uneven and follows exposure; artificial ageing tends toward uniformity, and lume that is uniformly 'aged' across every plot including the hands deserves scrutiny. Patina is evidence about a dial's history, never about a watch's authenticity.
Proof and Resist
Water Proof · Water ResistSeiko's two successive water-resistance dial legends. Earlier watches read 'Water XXm Proof'; from around 1970 the wording became 'Water XXm Resist', with the caseback stamping following.
Why it matters in examination
The most useful unmagnified era check on a vintage Seiko, and the one that most often exposes a mismatched dial and case. Dial and caseback wording should agree. The transition was not simultaneous across markets — North American 6139 examples are reported as 'Resist' from the outset — so the wording places a watch broadly rather than dating it.
Related terms Seiko date code
Redial
refinished dialA dial stripped and reprinted, usually to remove age damage. The result may be neat, but the original printing is gone.
Why it matters in examination
Among the most consequential findings on a vintage watch, and one of the most common. Typical signs are printing that sits on the surface rather than in it, minute tracks running under applied markers, text spacing inconsistent with the period, and lume plots that do not match the hands. A redial is an originality and value finding on a genuine watch — it is not, on its own, evidence of a counterfeit. It becomes the DOMINANT defect, rather than one finding among many, wherever a tidy dial adds more to the price than refinishing costs while a whole counterfeit would not pay: that describes vintage Tissot, Certina, Mido, Bulova, Yema, Zodiac and much of the rest of the accessible vintage market, where reaching for the word 'fake' will be wrong far more often than it is right. On brands where the dial colour is part of the model designation — Doxa's Sharkhunter, Searambler and Divingstar — a redial does not merely cost originality but changes what the watch IS.
Related terms Service dial · Tritium · Patina · Dial colour as model identity
Sandwich dial
A dial built from two plates with a luminous layer between them, the upper plate pierced so the lume is seen through the openings rather than applied on top of the dial.
Why it matters in examination
One of the few construction features that can be assessed in seconds without tools: under raking light the numerals are visibly recessed with a plate thickness at their edges. Printed imitations sit flush and show no depth. Note that not every Panerai uses one, so absence must be checked against the reference before it is reported.
Related terms Luminova / Super-LumiNova · Service dial
Secret signature (signature secrète)
The word CARTIER micro-printed inside one stroke of one Roman numeral on a Cartier dial, most often the VII. Introduced as an anti-counterfeiting device and requiring magnification to read.
Why it matters in examination
Routinely described as a test for a genuine Cartier, and it is not one. Counterfeiters reproduce it, so a signature that is present and well made is consistent with a genuine dial and with a good fake alike. Only its execution carries information, and only against what the reference should have — not every Cartier carries one, and a Cartier service dial carries a correct one.
Related terms Service dial · Redial
Service dial
A replacement dial supplied by the manufacturer during servicing, often printed to a later specification than the original.
Why it matters in examination
A service dial is the manufacturer's own part and is entirely legitimate. It commonly differs from the original in luminous compound and text, which examiners unfamiliar with the practice mistake for a redial or a fake. The distinction — factory original, service correct, refinished, counterfeit — is exactly what a four-way correctness classification exists to preserve.
Related terms Redial · Correctness classification
Snowflake
Collector name for the square-marker dial and angular-lozenge hand set used on Tudor Submariners from about 1969 to the mid-1980s. Tudor did not use the name at the time; it is collector vocabulary that the company later adopted in its own marketing.
Why it matters in examination
The dial and hands are Tudor's own parts on a watch whose case and bracelet are Rolex's, which makes them the components that carry the authentication weight — the reverse of the usual priority. They are also, for the same reason, the most reproduced. Dial and hands were lumed together, so comparing their ageing is the first check worth making.
Related terms Service dial · Redial · Patina
Tapisserie
Petite Tapisserie · Grande Tapisserie · Mega TapisserieThe Royal Oak's dial pattern: a grid of raised squares, each chamfered, machined into the dial. Three scales are used across the line, differing in square size, and the scale is model-specific rather than a decorative option.
Why it matters in examination
Machined rather than printed, so each square has real depth and a cut edge under magnification. That depth is difficult to reproduce and quick to inspect, which makes the dial a good early check alongside the bezel finishing.
Related terms Service dial · Perlage
Tropical dial
A black dial whose lacquer has oxidised over decades to brown. The effect is uneven ageing of a genuine original dial, and it commands substantial premiums.
Why it matters in examination
The premium is precisely why this is dangerous. Artificially browned dials are made, and the value gap between a black dial and a tropical one is large enough to justify considerable effort. Genuine tropical ageing is uneven and directional, consistent with how the watch was worn and stored, and it should be consistent with the ageing of the lume and hands. Uniform browning across a whole dial is a question rather than a prize.
Related terms Patina · Redial · Service dial
Unbranded dial
A production dial carrying no maker's name, no indices and no text of any kind, as a deliberate design decision — H. Moser & Cie.'s Concept line being the principal example.
Why it matters in examination
Disables most of the dial-based checks this catalog relies on, and creates a specific false-finding risk in the other direction. An examiner meeting an unmarked dial will reasonably suspect a refinished or replaced one, and on a Concept reference that inference is precisely wrong — the absence is the specification. Establish the reference BEFORE concluding anything from what is not on the dial. What survives is worth noting for its own sake: with printing removed, the dial's optical quality carries the evidential load, and a difficult finish such as a fumé gradient is a substantially harder thing to counterfeit than a printed wordmark. A brand doing this has swapped a cheap identifier for an expensive one.
Related terms Fumé (gradient) dial · Correctness classification
Escapement & regulation
Co-axial escapement
Co-Axial · Daniels escapementAn escapement designed by George Daniels and industrialised by Omega from 1999, using three pallets and a separate co-axial impulse wheel so that impulse is delivered radially rather than by the sliding action of a Swiss lever. The intent is to reduce sliding friction and so the dependence on lubrication.
Why it matters in examination
Visually unmistakable through a display back once known, and effectively impossible to fake on a movement that does not have one. That makes it a hard check rather than a soft one: a watch whose dial says Co-Axial and whose escapement is a Swiss lever is inconsistent, full stop. Note that the presence of a co-axial escapement does not by itself date a watch, since the escapement spans twenty-five years of production across many calibers.
Related terms Master Chronometer · COSC chronometer certification
Free-sprung balance
A balance regulated by adjusting weights or nuts on the balance rim, with no regulator index arm altering the hairspring's effective length.
Why it matters in examination
Among the most useful single checks available through a display back or on an opened watch. Rolex's 15xx, 30xx and 31xx families are free-sprung throughout; a regulator index on a movement presented as one of them is inconsistent with the caliber.
Related terms Microstella nuts · Regulator index · Glucydur
Gyromax balance
Patek's free-sprung balance, regulated by rotating weights set into the balance rim rather than by moving a regulator arm along the hairspring.
Why it matters in examination
Free-sprung means no regulator index, and its absence is checkable from a single photograph of the balance area. A movement presented as a modern Patek caliber that carries a regulator arm and index scale is inconsistent with the caliber — the same structural check that identifies a Rolex 3135, and for the same reason.
Related terms Free-sprung balance · Microstella nuts · Regulator index
Microstella nuts
Rolex's small star-shaped regulating nuts set on the inner face of the balance rim, turned to adjust the balance's inertia and thereby its rate.
Why it matters in examination
Distinctive in shape and position, and hard to reproduce convincingly on a movement built from a donor ébauche. Read alongside the balance bridge rather than alone.
Related terms Free-sprung balance
Modular escapement
An escapement built as a self-contained assembly that can be removed and replaced as one unit, rather than as components seated individually in the movement's plate.
Why it matters in examination
A structural identifier visible through a display back: the escapement reads as a discrete assembly rather than as parts distributed across the movement, and no amount of decoration applied to a generic caliber will reproduce it. It also has a real service consequence worth recording — the regulating assembly can be exchanged as a unit, so servicing is faster than the movement's complexity would suggest, and a serviced example may carry a replacement module rather than repaired original components. That is a manufacturer service configuration, not a fault.
Related terms Fumé (gradient) dial · Hand finishing as evidence
Natural escapement
An escapement derived from Breguet's design in which two escape wheels impulse the balance directly in both directions, eliminating the pallet fork and its sliding friction. Distinct from the Swiss lever escapement used in essentially every other mechanical watch.
Why it matters in examination
Among the most conclusive single observations available in this catalog, for the same reason as the Accutron's tuning fork: it is an architecture, not an appearance. A Swiss lever has one escape wheel and a pallet fork; a natural escapement has two escape wheels and none. No amount of finishing or decoration applied to a conventional movement produces that layout, and it is visible through a display back. Very few manufacturers build one — it is difficult to make work reliably — so its presence is strong positive evidence and its absence, on a watch claimed to have one, is decisive.
Related terms Low-volume manufacturer confirmation · Hand finishing as evidence
Regulator index
A moving arm on the balance cock carrying curb pins, which alters the hairspring's active length to speed or slow the movement.
Why it matters in examination
Its presence or absence identifies whole caliber families at a glance. Simple, decisive, and requires only a clear photograph of the balance area.
Related terms Free-sprung balance
Shock protection
Incabloc · KIF · ParaflexA sprung jewel setting for the balance pivots that lets them displace under impact rather than shear. Incabloc, KIF and Paraflex are the common systems.
Why it matters in examination
Each system has a distinct spring shape — Incabloc's lyre form is the most recognisable — so the setting identifies a movement family and sometimes a period. It is also a specification a caliber record can be checked against.
Related terms Jewel
Finishing & decoration
Anglage
bevelling · chamferingThe bevelling and polishing of a bridge or lever's edges, at its highest level performed by hand to produce mirror-bright surfaces and crisp interior angles.
Why it matters in examination
An interior angle — a sharp inward corner — cannot be produced by a rotating tool and is therefore direct evidence of hand finishing. One of the few finishing features that resists imitation, since faking it costs as much as doing it.
Related terms Côtes de Genève · Black polishing
Black polishing
spéculaire · mirror polishingA flat surface lapped until it reflects light in only one direction, appearing black from every other angle.
Why it matters in examination
Slow and skilled, and found on high-grade steel components such as chronograph levers and cap jewel settings. It has no machine equivalent, which makes it evidence rather than decoration — and the test is behavioural, needing only a loupe and a light: rotate the component, and a genuinely black-polished surface flips between deep black and bright white with no intermediate mottling, where a merely polished one shows graduated reflections. Paired with the internal-angle test on anglage — a rotating tool rounds internal corners and holds a uniform bevel width, while hand work reaches a sharp point and varies slightly along its length — it gives two geometric, non-aesthetic ways to separate hand finishing from machine finishing wherever hand work is part of the specification, as it is on Greubel Forsey, the Montblanc Villeret calibers and the independents generally.
Related terms Anglage · Multi-axis and inclined tourbillon · Hand finishing as evidence
Case-finishing examination (Royal Oak)
The practice of assessing a Royal Oak from the alternation of brushed surfaces and polished chamfers on its bezel and bracelet before examining anything else.
Why it matters in examination
The Royal Oak's value rests on hand finishing rather than on its movement, which for most of the line's life was a Jaeger-LeCoultre architecture also sold to Vacheron Constantin and Patek Philippe. Finishing is where counterfeits fail and where they cannot cheaply improve, because the cost is labour rather than tooling, and it is assessable in good light with no disassembly. The corollary: a third-party polish is not evidence of a counterfeit, but it destroys the signal and should be recorded as weakening every inference that follows.
Related terms Anglage · Black polishing · Correctness classification
Côtes de Genève
Geneva stripesParallel striping applied to bridges and rotors, produced by an abrasive tool traversing the surface.
Why it matters in examination
Execution differs sharply between grades. Properly finished bridges carry the striping to and under their edges with clean anglage; cheaply decorated ones show striping that stops short and edges left raw. Visible with a loupe through a display back.
Hand finishing as evidence
Movement decoration applied by hand rather than by machine — bevelled and polished edges, straight-graining, black polish — distinguishable from machine work by specific and consistent physical differences.
Why it matters in examination
One of the few places where finishing quality is evidence rather than taste, and the distinguishing feature is geometric rather than aesthetic: a rotating tool cannot reach into a sharp internal angle, so machine bevels round off at internal corners and are uniform in width, while hand bevels can be brought to a crisp point and vary slightly along their length. On calibers where hand finishing is part of the specification — Montblanc's Villeret Minerva movements, and the high-horology brands elsewhere in this catalog — its absence is a finding rather than a disappointment. Look at the internal angles.
Related terms Two manufactures under one brand
Hand-engraved balance cock
A balance cock engraved freehand, without a template, so that no two are identical. Used by A. Lange & Söhne on every movement it makes.
Why it matters in examination
The only individuating feature in this catalog — it identifies a watch rather than a model, which nothing else here does. Three consequences: photograph it, because the image can positively match a watch with a prior photographic record; treat machine-cut or stamped engraving as conclusive against the movement, because there is no fixed pattern for a counterfeit to copy; and treat two watches offered with identical engraving as the same watch or a copied photograph.
Related terms Anglage · Black polishing · Provenance
Perlage
circular grainingOverlapping circular graining applied to plates and to surfaces hidden under bridges.
Why it matters in examination
Its presence on concealed surfaces indicates finishing carried out for its own sake rather than for display, which is a meaningful grade signal — and one a decorated reproduction rarely bothers with.
Related terms Côtes de Genève
Thermal blueing
Colouring steel or titanium by controlled heating, so that an oxide layer grows in the surface of the metal and produces the colour. Distinct from paint, lacquer and PVD, which are applied on top of the metal.
Why it matters in examination
One of the most broadly applicable finishing checks in this catalog, since blued screws and blued hands appear across a great many watches. The distinguishing behaviour is at edges and under raking light: a thermal blue has depth, varies slightly across the surface and follows the topography, and it cannot chip to reveal a different colour because there is nothing beneath it but the same metal. A coating is uniform, levels the surface beneath it, and can wear at an edge to expose the substrate. A loupe on a screw head or a hand tip settles it. De Bethune applies the technique to titanium and to whole cases, which makes the check unusually easy to perform there, but the reasoning transfers to any blued component anywhere in the catalog.
Related terms Articulated lugs · Hand finishing as evidence
Luminous material
LumiBrite
Seiko's strontium-aluminate photoluminescent compound, introduced in the 1990s. It is charged by light and is not radioactive, unlike the tritium used on Seiko watches into the 1970s and 1980s.
Why it matters in examination
A dating and originality signal. LumiBrite in a watch whose case dates to the 1970s means the dial, the hands, or both have been replaced or relumed. It glows strongly and evenly where aged tritium is dull and uneven, so a mismatch between the dial's glow and the hands' is visible in a dark room and is one of the fastest checks on a vintage diver.
Related terms Hacking and hand-winding
Luminova / Super-LumiNova
Non-radioactive photoluminescent pigments that replaced tritium from the mid-1990s. They charge under light and require no radioactive decay.
Why it matters in examination
Its presence sets a lower bound on a dial's age. Luminova on a dial marked for tritium indicates a replacement or relumed dial — a finding about the dial, to be read before any conclusion about the watch.
Related terms Tritium
Tritium
A radioactive hydrogen isotope used in luminous compounds from the 1960s until its withdrawal in the 1990s, marked on dials by 'T' flanking 'SWISS MADE'.
Why it matters in examination
Tritium's activity decays with a half-life of about twelve years, so genuinely old tritium lume no longer glows meaningfully. Bright, even glow on a dial marked as tritium is a strong indicator of relumed or replaced material. Ageing produces cream and amber tones that are unevenly distributed — uniform colour across every plot is worth examining closely.
Related terms Patina · Luminova / Super-LumiNova · Redial
Manufacturing methods
Assembled versus manufactured
The distinction between a watch put together in a place and one whose components were made there. A watch assembled in Georgia from a Japanese movement, a Chinese case and a Swiss crystal is accurately described as assembled in Georgia and inaccurately described as made there.
Why it matters in examination
Marketing language routinely blurs this, and an examiner asked to verify a claim of origin needs the distinction to answer honestly. TSIKOLIA markets the Marina as the first automatic watch assembled in Georgia, which appears to be an accurate and carefully worded claim — the caliber is a Miyota 9015 and the wording says assembled. Reading it as a claim of Georgian manufacture would misrepresent what the maker actually said.
Related terms Ébauche · Provenance
Cartier Paris, London and New York
The three Cartier houses, which for much of the twentieth century operated with substantial independence — commissioning different cases, sourcing movements differently, numbering differently, and signing their dials for the house that sold the watch.
Why it matters in examination
Establish which house before applying any rule. A convention derived from Paris practice applied to a London watch produces a confident false finding, and the difference is not cosmetic: case makers, movement suppliers and numbering all differ. The signature also carries a price premium, which makes it a target for redialling and means it must be assessed as printing rather than read as text.
Related terms Provenance · Redial
Jaeger-LeCoultre as movement supplier
JLC's long-running role supplying movements to other houses, most consequentially the caliber 920 — which it never used in its own watches and which went to Audemars Piguet, Patek Philippe and Vacheron Constantin.
Why it matters in examination
Produces a specific and common false finding: a Jaeger-LeCoultre-derived caliber inside a Cartier, an AP or a Patek is very often CORRECT, and reading it as evidence of a marriage is a true observation leading to a wrong conclusion. The inverse also holds — because the 920 was never a JLC product, finding one in a watch signed Jaeger-LeCoultre is the situation that warrants a question.
Related terms Ébauche · In-house movement · Marriage
Micro-brand
A small independent watch company that designs and assembles watches around bought-in movements, typically selling directly and in quantities measured in hundreds or low thousands.
Why it matters in examination
Changes what an examination is for. A micro-brand watch is not counterfeited, because there is no secondary-market premium to capture, so the question is identification and completeness rather than deception. The evidence profile inverts too: the movement is a commodity ébauche with full manufacturer documentation behind it, while the watch itself has no archive, no collector literature and no auction record. Strong on the movement, thin on the watch — which is the reverse of every prestige brand in this catalog.
Related terms Ébauche · In-house movement
Movement-case number
Case number · Seiko reference numberSeiko's vintage reference format: a caliber code and a case design code joined by a hyphen, as in 6139-6002. The first group names the movement the watch was built around; the second identifies the case design and is unique only in combination with the first.
Why it matters in examination
It makes a movement check possible before the watch is opened, which no Swiss reference number does. It also means the reference is stamped on a part — the caseback — that unscrews, so the number establishes what the caseback is rather than what the watch is. Modern Seiko references such as SPB143 encode nothing at all and cannot be read this way.
Related terms Seiko date code · Dial code
PAM number
Panerai's product reference: PAM followed by five digits, assigned sequentially as references were introduced. It encodes nothing about the watch.
Why it matters in examination
An index into Panerai's catalogue rather than a code to decode, which makes it reliable for checking a watch against what it is sold as and useless for inference. Two traps: it identifies a configuration and never an individual watch, and because the numbers were assigned at introduction, adjacent PAM numbers can belong to watches made a decade apart.
Related terms Serial number
Patek reference suffix
The bracelet, metal and dial fields appended to a Patek model number — as in 5711/1A-010, where /1 denotes an integrated bracelet, A denotes acier (steel) and -010 a dial execution. The metal letters follow French: A steel, J yellow gold, G white gold, R rose gold, P platinum.
Why it matters in examination
The only genuinely decodable reference scheme in this catalog, and it turns the reference into a free four-point consistency test: the metal letter against the case, the bracelet field against whether the watch has an integrated bracelet or lugs, the dial code against the dial. A document naming a reference that contradicts the watch is an inconsistency to resolve before anything else is examined. It identifies a configuration, never an individual watch.
Related terms Serial number · Extract from the Archives
Product Identity Code (PIC)
PIC · Omega 14-digit referenceOmega's fourteen-digit product code, used from 2007, written as six dot-separated groups. It identifies one exact configuration of a model — case metal, size, dial, bezel and bracelet together — so any change to the specification produces a different code.
Why it matters in examination
Useful for verifying that a watch matches the product it is being sold as, because a PIC can be checked against Omega's own page for that configuration. Useless for authentication of an individual watch: every example of a configuration shares the code, and it appears on the card and box rather than on the watch, so it travels with paperwork rather than with the watch.
Related terms Serial number · Extract from the Archives
Rolex parts supply (vintage Tudor)
The arrangement by which Tudor built watches in Rolex-supplied Oyster cases with Rolex crowns, crystals and bracelets, around movements bought from ETA. It was the brand's founding commercial proposition rather than an incidental sourcing decision.
Why it matters in examination
Rolex case-maker marks and a coronet-signed crown on a vintage Tudor are CORRECT. Reading them as a marriage is a false finding drawn from a true observation. The arrangement also explains why original vintage Tudor bracelets are scarce: the parts interchange with Rolex, which gave them a market of their own.
Related terms Marriage · End link · Correctness classification
Suwa and Daini Seikosha
Suwa · Daini · SeikoshaThe two manufacturing companies inside Seiko that built watches in internal competition — Daini Seikosha in Tokyo, whose successor is Seiko Instruments, and Suwa Seikosha in Nagano, whose successor is Seiko Epson. Daini developed King Seiko; Suwa developed Grand Seiko, the 1969 quartz Astron and the 6139 chronograph. Their dial and caseback marks are a lightning bolt and a whirlpool respectively.
Why it matters in examination
The mark identifies the manufacturing entity, which should agree with the caliber's known origin. It is not a quality grade and neither factory outranks the other. Seiko stopped applying the marks as the companies were renamed, so their absence on later watches is expected — and because dials and casebacks separate, a mark identifies the part it is on, not the watch.
Related terms Dial code
Two manufactures under one brand
A brand whose output is produced at two facilities of entirely different character — a volume operation using outside movements and a low-volume manufacture making its own — under a single name and often within a single collection.
Why it matters in examination
Makes the FIRST question 'which production is this?' rather than 'is this genuine?', and everything else follows from the answer. Montblanc is the clearest example in this catalog: a Sellita movement is correct in a Le Locle watch and disqualifying in a Villeret one, and the two can look broadly similar in a photograph while differing by an order of magnitude in price. Collection names are no guide, because they cross the divide — Montblanc's 1858 collection is named for Minerva's founding year and contains watches with no Minerva content. Only the reference and the caliber settle it. The same structure appears wherever a group has acquired a manufacture and attached it to a volume brand.
Related terms Hand finishing as evidence · Generational redesign
Materials
Cerachrom
Rolex's ceramic bezel insert, introduced in 2005, with the numerals recessed into the ceramic and filled with platinum or gold by PVD deposition rather than printed on the surface.
Why it matters in examination
The construction is the check rather than the colour: on a genuine insert the numerals sit BELOW the surface with metal in the groove, which under a loupe looks entirely different from ink lying on ceramic. Ceramic also does not fade, so a Cerachrom insert showing the sun-fading that makes vintage aluminium inserts desirable is not behaving like ceramic.
Related terms Patina · Correctness classification
Glucydur
A beryllium-bronze alloy used for balance wheels, valued for its hardness, low thermal expansion and resistance to corrosion.
Why it matters in examination
A specification claim rather than a visual one: it appears in technical documentation and cannot reliably be confirmed by eye. Useful for checking a listing against a caliber's documented specification.
Related terms Free-sprung balance
Hardness versus toughness
Two distinct and largely opposed material properties. Hardness is resistance to scratching and abrasion; toughness is resistance to fracture under impact. Engineering ceramics and cemented carbides are far harder than steel and far less tough.
Why it matters in examination
Governs how damage should be read on ceramic, hardmetal and sapphire components, and it runs opposite to the intuition an examiner builds on steel watches. On steel, scratches are ordinary wear and a chip suggests abuse. On these materials the reverse holds: fine scratching should be ABSENT and a chip or crack is the expected mode of failure. A scuffed case claimed as ceramic or hardmetal is a material finding; a chipped one is merely damaged. Getting this backwards is the commonest way a genuine Rado, or any ceramic-bezel watch, is wrongly reported as suspect.
Related terms Testable material claim · Thermal behaviour as a material test
Hesalite
Omega's designation for the acrylic crystal used on the Moonwatch. It crazes under impact rather than shattering, which is why it was qualified for spaceflight.
Why it matters in examination
Later Hesalite crystals carry a small centre-etched Omega logo, visible at an angle. Its absence dates a crystal or indicates a replacement, and does not by itself indicate anything else.
Related terms Crystal
Poinçon
French hallmark · Assay markA mark struck by a French state assay office certifying the fineness of a precious-metal article, together with a lozenge-shaped responsibility mark identifying the maker or sponsor. The eagle's head certifies 18-carat gold; the dog's head certifies 950 platinum.
Why it matters in examination
The strongest class of marking on a vintage watch, because it is struck by the state under statute rather than by the maker. Its force is asymmetric: presence is expected and proves little, absence where the mark would be compulsory is a finding that precedes every other question. On Cartier specifically, a maker's responsibility mark that is not Cartier's is normal — the company commissioned its cases — and reading it as a replaced case is a common error.
Related terms Provenance · Correctness classification
Testable material claim
A stated case material — ceramic, titanium, carbon composite, sapphire — whose physical properties differ measurably from steel in weight, hardness and thermal behaviour.
Why it matters in examination
One of very few claims in this catalog an examiner can check in the room with no equipment. A ceramic or titanium case has a distinctly different weight from steel and takes heat from the hand at a different rate, so a case that warms like metal is not ceramic whatever the reference says. On brands whose reference numbers encode the material — Hublot's second field, Patek's metal letter — this turns the reference into a claim to be verified rather than information to be accepted.
Related terms Cerachrom · Correctness classification
Thermal behaviour as a material test
Judging a case or bezel material by how quickly it takes heat from the hand. Metals conduct heat well and warm rapidly; engineering ceramics conduct poorly and stay cold noticeably longer.
Why it matters in examination
The most efficient material test available to an examiner with no equipment, and the one that defeats the standard ceramic counterfeit — black-coated steel — outright. It cannot be engineered around, because it is a bulk property of the material and not of the surface, so a coating that looks perfect fails it anyway. On mixed-material watches such as the Rado Integral it is better still, because the ceramic and metal elements can be compared against each other on the same wrist at the same time. TWO DOCUMENTED EXCEPTIONS, both on Rado, and both of which invert the naive reading: PLASMA high-tech ceramic is carbon-enriched to look like brushed metal while remaining ceramic, so a metallic-looking case that stays cold is correct rather than contradictory; and CERAMOS is a cermet containing a metallic binder, so it warms more than pure ceramic and the test should be applied loosely there, with weight used instead. Establish the specified material before interpreting the result.
Related terms Hardness versus toughness · Testable material claim
Untreated German silver
Nickel silver · NeusilberA copper-nickel-zinc alloy used unplated for movement plates and bridges, principally by Glashütte makers. Harder to finish than plated brass, and it oxidises slowly to a warm honey tone.
Why it matters in examination
The patina is expected and desirable, so an untoned plate on a watch of age is a question — usually meaning it has been cleaned. That matters because cleaning German silver is irreversible damage rather than restoration: the tone cannot be restored and the movement's visible age is gone. Report it as permanent.
Related terms Patina · Côtes de Genève · Perlage
Movement architecture
Balance bridge
A balance support anchored at both ends, as distinct from a balance cock anchored at one. The two-point mounting resists shock displacement better.
Why it matters in examination
The full balance bridge is a signature of the Rolex 3135 and its relatives. A single-anchor cock on a movement presented as a 3135 is inconsistent with the caliber and is one of the strongest quick checks on the movement side.
Related terms Free-sprung balance
Bumper automatic
An early self-winding design in which the weight swings through a limited arc and strikes sprung buffers at each end of its travel, rather than rotating continuously through 360 degrees.
Why it matters in examination
Identifiable through a closed case: the weight arriving at its buffers produces a distinct knock felt through the watch as it moves, where a rotating weight is silent. That makes it one of very few caliber-generation checks in this catalog that requires neither tools nor opening the watch. On the Universal Genève Polerouter it pairs with the dial spelling — but ASYMMETRICALLY, and the direction matters. Every POLAROUTER-spelled watch has the bumper 138SS, so a Polarouter dial over a silent micro-rotor is an inconsistency. The converse does not hold: the earliest POLEROUTER-spelled watches also carry the bumper, because the name changed before the movement did. A knocking early Polerouter is correct.
Related terms Micro-rotor
Dial-side architecture
A construction in which movement components are mounted on the front of the watch and form the dial, rather than being concealed behind it.
Why it matters in examination
Puts an examiner in the strongest position available, because a movement that IS the dial cannot be substituted behind one. The check reduces to comparing visible architecture — component positions, bridge shapes, train layout — against the published caliber, and there is nothing to conceal a mismatch. Where the exposed mechanism drives an observable behaviour, as with a true-beat seconds on the Arnold & Son DSTB, cause and effect can be watched together, which is stronger than either observation alone. That last point matters more than it sounds: a quartz movement also steps its seconds hand once per second, so the STEP is not evidence of a true beat — the visible mechanism producing it is.
Related terms Revived historical name · Functional complication test
ETA / manufacture boundary (Tudor)
The point from 2015 at which Tudor introduced its own MT56xx calibers alongside, and then largely in place of, the bought-in ETA movements it had used since the 1950s.
Why it matters in examination
The most useful configuration fact on the brand, and checkable without opening the watch: the MT56xx calibers carry roughly a 70-hour power reserve against the ETA's roughly 38 to 42. It is a dating and configuration boundary, not a quality judgement, and reporting an ETA in a pre-2015 reference as a finding is a common and avoidable error.
Related terms Ébauche · In-house movement · Power reserve
Hacking and hand-winding
Hacking is the stopping of the seconds hand when the crown is pulled to set the time. Hand-winding is the ability to wind the mainspring through the crown. Several major Seiko calibers — the 7S26 and the 6309A among them — have neither.
Why it matters in examination
The most valuable non-invasive check available on a Seiko, because it separates calibers that are otherwise indistinguishable without opening the watch. A hacking 6306A against a non-hacking 6309A is the difference between a JDM Turtle and an export one; a hacking movement in a watch presented as an original SKX007 means the 7S26 has been replaced. It takes seconds and requires no tools.
Related terms Magic Lever
High-frequency quartz
A quartz movement running an oscillator substantially faster than the industry-standard 32,768 Hz — Bulova uses 262,144 Hz — permitting finer timing resolution and a seconds hand whose increments are small enough to read as a continuous sweep.
Why it matters in examination
Breaks the most widely used shortcut in casual watch identification. Sweep-versus-step is commonly treated as the test for mechanical against quartz, and on a high-frequency quartz watch it gives the wrong answer in both directions: the examiner either takes a quartz watch for a mechanical one, or reports a correct sweep on a watch specified as quartz as evidence of a substituted movement. Where a brand is known to use high-frequency quartz, the sweep is a brand signature and settles nothing about the movement type.
Related terms Tuning-fork movement
In-house movement
A movement designed and manufactured by the watch house that sells it, as opposed to a bought-in or modified ébauche. The term has no legal definition and is used with varying strictness.
Why it matters in examination
A marketing claim more often than a technical one. Because no standard governs it, 'in-house' on a listing is not a specification an examiner can check, and it should never be used to date or identify a caliber.
Related terms Ébauche
Jewel
A synthetic ruby or sapphire bearing set at a pivot or impulse surface to reduce friction and wear.
Why it matters in examination
Jewel count is a caliber specification, and a count differing from the documented figure is worth resolving — but often the resolution is that the count changed during production, as it did on the Omega 861. A mismatch is a research prompt, not a finding.
Related terms Shock protection
MC (Manufacture Cartier)
The suffix Cartier applies to its caliber numbers, standing for Manufacture Cartier — as in 1847 MC, 1904-PS MC, 430 MC.
Why it matters in examination
The designation is less informative than it appears and should not be read as a guarantee of in-house design. The 430 MC is a Piaget 430P finished for Cartier, a movement from within the same group. Read the movement's architecture rather than its designation, and expect a supplier's bridge layout wherever the caliber has a supplier's ancestry.
Related terms In-house movement · Ébauche
Magic Lever
Seiko's bidirectional automatic winding system, using a pawl-lever mechanism that winds on rotor movement in both directions with very few parts. Introduced in the late 1950s and still in use across the current range.
Why it matters in examination
Its simplicity is why Seiko automatics from the 7S26 upward are reliable and cheap to service, and it is a recognisable feature on the movement side of a watch — useful when confirming that a movement is what a dial claims.
Related terms Hacking and hand-winding
Mainspring barrel
The drum housing the mainspring, whose size and count set the power reserve and the evenness of torque delivery.
Why it matters in examination
Twin barrels explain outlying power reserves — IWC's seven-day calibers and Omega's 8500 among them — and are visible through a display back.
Related terms Power reserve
Micro-rotor
A winding rotor recessed into the movement plate rather than riding above it, reducing overall height at the cost of winding efficiency. Arrived commercially in 1955, in Universal Genève's caliber 215 and Buren's contemporaneous work.
Why it matters in examination
Immediately visible through a display back or on opening, and decisive for caliber identification: a full overhead rotor on a watch presented as carrying a micro-rotor caliber — the Patek 240, the Universal Genève 215 or its Shadow-era successors — is inconsistent with the movement, most often because the original was replaced during a repair. It constrains the CASE as well as the movement: micro-rotor watches were designed thin because thinness was the entire purpose, so an unexpectedly thick case on such a reference is itself a finding.
Related terms Peripheral rotor · Bumper automatic
Module
A self-contained complication mechanism mounted on top of a base movement rather than integrated into it — most commonly a chronograph or a calendar.
Why it matters in examination
Modular construction leaves visible traces: added movement height, pushers or a crown in unusual positions, and a base caliber that can be identified independently of the complication. The left-hand crown of the Chronomatic Caliber 11 is a direct consequence of its module.
Related terms Integrated chronograph · Ébauche
Movement grade as product identity
A manufacturing and retail model in which the manufacturer sells a numbered MOVEMENT GRADE rather than a complete watch, leaving the purchaser to buy a case separately — standard practice in American watchmaking into the mid-twentieth century.
Why it matters in examination
Inverts two habits an examiner brings from modern watches. First, the identity of the watch lives on the movement, not on the case or a reference number, so a Hamilton 992B is a 992B whatever case it sits in. Second, and more consequentially, a case and movement by different makers is the NORMAL condition rather than evidence of a marriage — treating a Wadsworth case on a Hamilton movement as a red flag would condemn most surviving American railroad watches. Where value differs between grades, the fraud follows the grade marking on the movement rather than the watch as a whole.
Related terms Correctness classification · Serial block assignment
Parachrom hairspring
Rolex's in-house paramagnetic hairspring alloy, introduced around 2000 in a natural finish and later in the familiar blue.
Why it matters in examination
Dates a MOVEMENT, or its last service, rather than a watch. A blue Parachrom hairspring in an early 3135 is a service replacement and entirely legitimate; treating it as an inconsistency is one of the most common misreadings on the brand. The blue finish rolled out across the range over several years rather than on one date, so a movement from the transition may correctly have either.
Related terms Free-sprung balance · Microstella nuts · Service dial
Patek Philippe Seal
Patek's own certification, introduced in 2009 in place of the Geneva Seal. It covers the complete watch rather than the movement alone, applies rate tolerances tighter than COSC's, and carries a lifetime service commitment.
Why it matters in examination
A broader standard than the Geneva Seal and a less independent one — the manufacturer certifying its own work rather than the Canton certifying it. Worth stating precisely to a client who asks what it guarantees. Its practical use to an examiner is chronological: Patek stopped applying the Geneva Seal when it adopted this, so the two are a dating boundary at 2009 and each is an anachronism on the wrong side of it.
Related terms Geneva Seal · COSC chronometer certification · Master Chronometer
Pellaton winding
IWC's automatic winding system, designed by Albert Pellaton, in which a heart-shaped cam on the rotor arbor drives a pair of pawls that ratchet the barrel in both directions of rotor travel — in place of a reversing-wheel train.
Why it matters in examination
Looks like nothing else through a display back, which makes caliber-family identification genuinely visual on a brand where it is often hard. A movement presented as a 32xxx, 52xxx or 82xxx that winds through a conventional reverser is not what it claims. The later ceramic pawls and cam address wear that the steel components suffered, so their presence also places a movement in a generation.
Related terms In-house movement · Power reserve
Peripheral rotor
A full-diameter rotor riding on a bearing race at the movement's edge rather than on a central post — the solution the Jaeger-LeCoultre 920 uses to combine a full rotor with an ultra-thin profile.
Why it matters in examination
The mounting is unmistakable once seen and identifies the 920 family, including its Audemars Piguet, Patek Philippe and Vacheron Constantin executions.
Related terms Micro-rotor
Power reserve
The running time a fully wound movement delivers before stopping, determined by barrel and mainspring design.
Why it matters in examination
A practical dating tool where a house has raised it across a generation: 48 hours versus 70 distinguishes a Rolex 3135 watch from a 3235 one, and a Tudor ETA-caliber Black Bay from an MT56xx.
Related terms Mainspring barrel
Reduced beat rate for extended power reserve
The deliberate slowing of a movement's balance — typically from 28,800 to 21,600 vph — as part of reworking an existing caliber to run substantially longer on one barrel.
Why it matters in examination
A modern Swiss watch beating at 3 Hz reads as wrong to anyone used to 4 Hz movements, and on the ETA C07 family and its Hamilton, Tissot, Certina and Mido derivatives it is exactly right. The slow beat, the 80-hour reserve and the escapement material go together, and a timing trace showing 21,600 vph on such a watch confirms the caliber rather than casting doubt on it. The corollary is a real service finding: these movements are not interchangeable with their standard-beat ancestors at the escapement, so one rebuilt with ordinary 2824 parts will run but will not hold the reserve.
Related terms Movement grade as product identity
Serial block assignment
The factory practice of assigning a block of serial numbers to blank movement plates which are then stored and finished as demand requires, so that a movement's serial number records when the number was allocated rather than when the watch was completed.
Why it matters in examination
Puts a documented, irreducible tolerance on serial-number dating. A Hamilton whose serial implies 1948 may genuinely have been finished in 1951, and the gap is a property of the production system rather than a weakness in the sources. This matters most when the serial date is being used as the yardstick for whether a dial, hand set or case is period-correct: a component judged wrong by two years may be entirely correct. Prefer conclusions that tolerate a few years of slack, and treat any authentication argument that turns on an exact serial year with suspicion.
Related terms Movement grade as product identity
Superlative Chronometer
Rolex's own certification, applied after COSC certification to the cased-up watch rather than the bare movement, to a tolerance Rolex sets and publishes.
Why it matters in examination
Frequently treated as a stronger version of COSC certification, which misstates what it is. COSC and METAS are outside bodies; Superlative Chronometer is the manufacturer testing its own finished product to its own published standard. That is a meaningful claim and a different kind of claim, and the distinction matters when a client asks what the dial text guarantees. Its practical use to an examiner is consistency: the text must agree with the caliber underneath it.
Related terms COSC chronometer certification · Master Chronometer
Suspended balance
A balance wheel mounted above the dial on a raised bridge rather than within the movement, fully exposed to view.
Why it matters in examination
Combines a functional check with a structural one, which is why it is stronger than either alone. The balance must be OSCILLATING — reversing direction constantly, unlike a decorative wheel that rotates — and the case must be built to accommodate it, so the crystal has to be domed high enough to clear the assembly. An examiner therefore has two independent tests: watch the balance move, and look at the case in profile. The profile view is worth requesting explicitly when assessing remotely, since a flat or shallow crystal on a watch claiming this construction is a contradiction that no photograph taken from directly above will reveal.
Related terms Published collaborator attribution · Compound curvature
Tuning-fork movement
An electronic movement in which a battery-driven tuning fork vibrating at a fixed high frequency — 360 Hz in Bulova's Accutron — replaces the balance wheel and escapement, its vibration converted to rotation by a pawl acting on a fine index wheel.
Why it matters in examination
Produces two behaviours no other movement type can: an audible continuous hum, and a seconds hand that advances with no perceptible increment whatever. Together they constitute the most nearly conclusive single-observation test in this catalog, admitted as such because they follow from the operating principle rather than from appearance — a movement that does not work this way cannot imitate them. The practical caveat is that the test needs a running watch, and surviving tuning-fork watches are very often not running: the movements need a specific supply voltage the original cells no longer provide, and the index and pawl fingers are fragile.
Related terms High-frequency quartz · Correctness classification
Ébauche
ebaucheAn unfinished movement — plates, bridges, going train and barrel — supplied by a specialist maker for a watch house to finish, regulate and brand as its own caliber.
Why it matters in examination
Explains why watches from unrelated houses share an architecture, and why a caliber number is a house's designation rather than a statement of who built the movement. An examiner who reads 'in-house' as 'unique construction' will mis-attribute a great many genuine movements.
Related terms In-house movement · Module
Provenance & documentation
Brand without a surviving archive
A manufacturer whose production records did not survive its history — through bankruptcy, sale, dormancy or destruction — so that no individual watch can be confirmed against factory documentation.
Why it matters in examination
Changes what an authentication can honestly conclude, and changes the weight of every other source. Where a Rolex or an Omega claim can ultimately be tested against the maker, a Universal Genève claim cannot, and no amount of confidence in the examiner substitutes for that. Three practical consequences: auction-house condition reports and long-standing dealer records rise in evidential weight because nothing outranks them; physical evidence such as interior case stamping becomes irreplaceable, so polishing destroys evidence rather than merely value; and any offer of manufacturer confirmation should be treated as a claim to be investigated. Note also that acquiring a dormant brand's intellectual property, as happened here in 2023, does not recover its archive.
Related terms Micro-rotor · Redial
COMEX
Compagnie Maritime d'Expertises, the French commercial diving company for which Rolex made issued Submariner and Sea-Dweller variants carrying COMEX dial text and issue numbers on the caseback.
Why it matters in examination
Among the most forged provenance claims in watch collecting, for the ordinary reason: the marks are a dial signature and an exterior caseback engraving, both addable, and the value multiple is large. The catalog's position mirrors the Tudor military engravings — a COMEX claim is unverified until the engraving's execution, the watch's configuration and an independent documentary chain agree, and no combination of correct-looking parts substitutes for provenance.
Related terms Provenance · Marriage · Franken watch
Commemorative versus issued
The distinction between a commercially sold watch carrying service-themed branding and a watch procured and issued by a service, which carries marks struck by that service.
Why it matters in examination
The two are constantly conflated in listings and the consequences run in both directions. A commemorative edition described as military-issued is a misrepresentation of what it is. Equally, applying the scepticism this catalog reserves for issue claims — the Tudor naval engravings, the IWC Air Ministry markings — to a themed commercial product would be wrong, because no issue is being claimed and there is nothing to doubt. Establish which class of object is in front of you before deciding which standard of proof applies.
Related terms Provenance · Correctness classification
Corporate discontinuity
A break in a brand's ownership and manufacturing continuity — bankruptcy, dormancy, sale of the name — across which the design language continues but the company does not.
Why it matters in examination
Creates the condition in which generations get conflated: the watches look continuous and the businesses are not, and the value gap across the break is usually large. Zodiac, Doxa, Universal Genève and Yema all have one in this expansion. The practical method is to find a feature that COULD NOT cross the break — a movement from a supplier that did not exist before the new ownership, a case material introduced later, a crystal type — rather than reasoning from design, which is precisely what the reissue reproduces. On Zodiac the STP caliber does this job cleanly: Fossil founded STP in the 2010s, so its presence dates a watch conclusively regardless of how faithfully the design quotes 1953.
Related terms Brand without a surviving archive · Mystery display
Extract from the Archives
A document issued by a manufacturer confirming what its records hold for a given serial — typically the production or sale date and the original configuration.
Why it matters in examination
Among the strongest provenance documents available, and among the most forged. It attests to what the archive holds for those numbers, not to the watch in front of you: the numbers must be read off the watch and the document verified with the manufacturer, never accepted from a photograph.
Related terms Serial number · Provenance
Flown watch versus flown model
The distinction between the individual watch that went to space and the production model sharing its design — the Yema Spationaute of Soyuz T-6, the Bulova chronograph of Apollo 15, the Omega of the Moon landings.
Why it matters in examination
Space provenance is the most valuable and most inflated claim in watch collecting, and the inflation usually happens through this exact elision rather than through outright fraud. One watch flew; it is an individually identified object with a documented history and, usually, a known owner or institution. Every other example of the model shares its design and none of its history. A production watch legitimately carries the MODEL's association and should be described that way — the useful test of a listing is whether it distinguishes the two, because a seller who does not may not know the difference, and a seller who does is choosing not to.
Related terms Limited-edition numbering · Observatory certification
JDM
Japanese domestic marketA watch produced for sale within Japan rather than for export. On Seiko the distinction is frequently substantive rather than cosmetic: JDM references may carry a different caliber, a Kanji day wheel, or a specification not offered elsewhere, as with the 6306 against the export 6309.
Why it matters in examination
Two consequences. First, a JDM reference bought outside Japan will usually have arrived through parallel import, so the absence of local warranty paperwork is expected and says nothing about the watch. Second, where the JDM version is the better-specified one, misrepresentation runs in that direction — check the specification difference itself rather than the caseback number that claims it.
Related terms Hacking and hand-winding
Licensed collaboration edition
A limited edition produced under licence from a third party — a musician, an estate, a record label, a sports body — carrying that party's marks or artwork under contract.
Why it matters in examination
Adds a second body of external evidence, because the licensor's marks have their own usage standards and their reproduction was contractually controlled. An unlicensed copy typically reproduces the artwork from press images, which shows at magnification in colour registration and edge definition. It also raises the documentary stakes: these editions are sold with certificates and presentation material that form part of what is being bought, so matching numbers across watch, certificate and packaging is a real check rather than a courtesy. Where the licensor is still active, the edition's existence and size are usually independently announced by both parties.
Related terms Limited-edition numbering
Limited-edition numbering
An individual number and a stated edition size engraved on a watch — typically as a fraction on the caseback — recording its place within a production run the manufacturer has publicly limited.
Why it matters in examination
One of the few claims in watch authentication that can yield a definite arithmetic contradiction: an edition of 500 has no number 640, and no amount of interpretation changes that. Where the manufacturer has published the edition size, the numbering is checkable against a source outside both the watch and the seller. The asymmetry is important and easily missed — a number OUTSIDE the range is close to conclusive, while a number inside it proves only consistency, since numbers can be engraved by anyone. It produces a strong negative and a weak positive, and HOW weak depends on the run: Raymond Weil's music editions run to 1,500 and 3,000 pieces, so a plausible number on one of those excludes almost nothing, where the same number on an edition of twenty would be meaningful. Read the size before reading the number. The related and more common problem is a standard reference described as an edition, which is a description failure rather than an authenticity one and is settled by the absence of any number at all.
Related terms Testable specification · Correctness classification
Low-volume manufacturer confirmation
Verification of an individual watch against the records of a manufacturer whose annual output is small enough — dozens to a few hundred pieces — that it knows each watch individually.
Why it matters in examination
The strongest evidence available on the independent tier, and the step most often skipped. A maker at this scale can confirm a serial, its original specification and its service history, which no physical examination can match. Two points about how it should be read. The asymmetry is the reverse of the industrial case: at Rolex volumes a manufacturer's silence on a serial means nothing, while at a hundred watches a year it means a great deal, so a failure to confirm is itself a finding here. And the request is best routed through the owner, since a manufacturer may properly decline to discuss a client's watch with a third party — a refusal on confidentiality grounds is not a refusal on authenticity grounds, and conflating the two would be unfair to both.
Related terms Natural escapement · Brand without a surviving archive
Moonwatch
Collector and, latterly, manufacturer shorthand for the Speedmaster Professional in the lineage NASA flight-qualified for manned spaceflight. It denotes a family of references rather than one, and its boundaries are conventional rather than defined.
Why it matters in examination
The term is used in listings to imply a specific provenance the watch usually does not have. A Moonwatch is a model designation; it is not a claim that the watch went anywhere. Establish which reference is in front of you and treat the nickname as an index term, never as a fact about the individual watch.
Related terms Provenance · Hesalite
Observatory certification
Precision certification granted by an independent astronomical observatory — Kew, Neuchâtel, Geneva, Besançon — on the basis of measured timing performance under controlled test over a period of weeks, rather than on manufacturer self-assessment.
Why it matters in examination
Among the few historical quality claims a catalog can treat as genuinely verifiable, because it was awarded by a third party, on measured performance, and recorded institutionally. Where a period watch or manufacturer claims observatory certification, there is in principle a record to check it against — which is not true of almost any modern marketing claim, and not true of most historical ones either. Baume Frères's Kew awards are the instance in this catalog. The practical caution is that a manufacturer's historical certification attaches to the watches that were tested, not to everything the manufacturer subsequently made, and marketing routinely blurs that.
Related terms Testable specification
Pre-1993 Panerai
Vintage Panerai · Military PaneraiThe instruments Panerai made for the Italian navy before it became a consumer brand in 1993, using cases and movements supplied by other companies and made in quantities measured in hundreds.
Why it matters in examination
A different object from a modern Panerai and governed by different rules. The population is tiny, the documentation is fragmentary military record rather than manufacturer archive, and the values make forgery rational at almost any cost — including assembling complete watches from period-correct parts. Community consensus is weaker evidence here than elsewhere, because a small population means a few accepted forgeries can shift the consensus itself. Treat as unverified absent an unbroken documented chain of custody, and decline rather than reason from general principles without specialist experience of these specific watches.
Related terms Marriage · Franken watch · Provenance
Provenance
The documented ownership and service history of a specific watch — original papers, service records, sale records, photographs.
Why it matters in examination
Provenance and authenticity are separate questions that reinforce one another. Strong provenance cannot make an incorrect watch correct, and its absence is normal rather than suspicious: most watches simply lose their paperwork.
Related terms Extract from the Archives · Serial number
Published collaborator attribution
A manufacturer's public naming of the independent constructors, finishers and specialists who built a given movement, as against presenting it as an institutional product of the brand.
Why it matters in examination
Supplies documentary evidence about a movement's ORIGIN, which is otherwise among the hardest things to establish. Most brands present movements institutionally, so an examiner can judge how a movement was made but rarely by whom; where the attribution is published — MB&F names its collaborators as a matter of principle — a claim about a movement's construction can be checked against the manufacturer's own account. It also cuts the other way, and usefully: a stated construction that does not match the published attribution is a documentary finding, arrived at without touching the watch.
Related terms Suspended balance · Low-volume manufacturer confirmation
Revived historical name
A modern company operating under the name of a historical watchmaker with which it has no manufacturing or corporate continuity — the name having been acquired, registered or simply adopted long after the original ceased.
Why it matters in examination
Distinct from corporate discontinuity, where a business survives a break: here there is no thread at all, only a name. Arnold & Son is the clearest case in this expansion — John Arnold worked in London from the 1760s, the modern Swiss company dates from 1995 — and the same structure applies to a number of revived marques. Two consequences for a report. Historical claims made by the modern brand describe an eighteenth-century maker's achievements and not the manufacturer of the watch in hand, and they should be attributed accordingly. And the historical objects themselves are museum-grade items with their own scholarship and their own market, entirely separate from the modern watches; a provenance claim that slides between the two is describing something that does not exist.
Related terms Corporate discontinuity · Dial-side architecture
Revived marque
A brand name relaunched by new owners after a period of dormancy, selling watches that reference the original company's designs and history.
Why it matters in examination
Creates a specific evidential problem: the modern company's account of the historical company is usually the primary source for that history AND part of the proposition being sold, so it corroborates itself and nothing more. Historical claims arriving only from the revived company should be recorded as unverified rather than repeated — not out of scepticism about the company, but because the same standard applied to a military engraving must apply to a claim that arrives without even an engraving to examine.
Related terms Provenance · Franken watch
Seiko date code
Seiko serial number · Caseback date codeThe six-character caseback code whose first character is the last digit of the production year, whose second is the month (1–9, then O for October, N for November, D for December), and whose remaining four are a sequential unit number within that month.
Why it matters in examination
It gives a month directly and a year only modulo ten, so the decade must be resolved from the reference's production window, the caliber, or the dial-text era. A decoder that returns a single year from the serial alone has guessed. And a serial that fits is never evidence of authenticity — numbers are copied onto counterfeits from genuine watches.
Related terms Movement-case number · Proof and Resist
Serial number
A manufacturer-applied number identifying a case or a movement, sequential in some schemes and deliberately randomised in others.
Why it matters in examination
Places a watch in a production window where the scheme is sequential, and does nothing at all where it is randomised. Serials are copied onto counterfeits — including real serials taken from genuine watches — so a serial that 'checks out' is not evidence of authenticity. It is one input to dating.
Related terms Rehaut · Extract from the Archives
The 1979 Breitling discontinuity
Willy Breitling sold the business in 1979 and the name was acquired and relaunched by Ernest Schneider in the mid-1980s. Company records from before the sale did not pass intact to the current company.
Why it matters in examination
A pre-1979 Navitimer and a post-1984 Chronomat are products of two different companies sharing a name, and no rule derived from one applies to the other. It also explains why Breitling offers no archive service reaching back to the vintage watches: there is no archive to search, which puts vintage Breitling closer to Tudor than to Omega in what can be established.
Related terms Provenance · Extract from the Archives
The 1985 Heuer / TAG Heuer boundary
The change of dial signature that followed Techniques d'Avant Garde's acquisition of Heuer in 1985. The plain Heuer name has since been revived on heritage reissues.
Why it matters in examination
Dates a dial, not a watch — and that distinction is the whole point. A TAG Heuer signature on a 1960s watch usually means a service dial fitted after the change; a Heuer signature on a current watch usually means a reissue. Both are correct configurations, and an examiner who reasons from the signature straight to a production year will be wrong in both directions.
Related terms Service dial · Redial · Provenance
The Lange discontinuity, 1948 to 1990
The period during which A. Lange & Söhne did not exist as a company, following post-war expropriation and absorption into the state combine at Glashütte. The name was refounded by Walter Lange in 1990 and the first modern watches appeared in 1994.
Why it matters in examination
Sharper than any other discontinuity in this catalog. A pre-war Lange pocket watch and a modern Lange 1 are products of two organisations separated by four decades, and no convention, numbering scheme or finishing standard carries across. Everything in the catalog's Lange records concerns the post-1994 company; a pre-war watch is a different subject requiring different sources.
Related terms Provenance · Extract from the Archives