Authentication Standards

Hublot · Big Bang Unico · Ref. 421.NX.1170.RX

Genuine cases combine precisely finished layers (ceramic, titanium, King Gold, carbon) with sharp satin/polished transitions; soft edges or mismatched materials indicate a fake.

Rolex · Submariner No Date · Ref. 124060

The 41mm case abandoned the 114060 'Super Case' proportions; exaggerated broad lugs on a 124060 are wrong.

Rolex · Submariner Date · Ref. 126610LN

The 126610LN grew to 41mm with slimmer lugs and 21mm lug width; a 40mm case or Super-Case lugs are inconsistent with the reference.

Rolex · Explorer II · Ref. 216570

The 216570 is 42mm with broad Maxi lugs; a 40mm case cannot be a 216570. This is the clearest 16570-vs-216570 differentiator.

Rolex · Sea-Dweller · Ref. 126600

The 126600 grew to 43mm and, uniquely for the Sea-Dweller, added a date Cyclops. Earlier Sea-Dwellers have no Cyclops and are 40mm.

Rado · Ceramica · Ref. Ceramica (high-tech ceramic platform)

Ceramic is hard and brittle. Dropped watches crack or chip where steel would dent, and the damage is generally not repairable. Record it as condition. It is also, incidentally, corroboration of the material: coated steel does not fail this way.

Seiko · Tuna · Ref. 6159-7010

The titanium case is opened from the front, so there is no screw-off caseback carrying a case number and serial in the usual place. Examiners expecting the standard Seiko caseback layout should not treat its absence as a missing or replaced part. Identification and dating rest on the shroud markings, the movement and the case's own stamping.

Rado · DiaStar Original · Ref. DiaStar 1 (1962)

Hardmetal is very substantially harder than steel and does not scuff in ordinary wear. A case presented as hardmetal that carries the fine scratch haze normal on a worn steel watch is either steel, or plated, or has met an abrasive it should not have. The case can still be DENTED and can CHIP — hardmetal is hard and brittle rather than tough — so a chip at an edge is consistent with the material where a field of light scratches is not. That distinction is the whole check and it is easy to get backwards.

MB&F · Horological Machine · Ref. Horological Machine

Each Horological Machine is a specific three-dimensional geometry produced in very small numbers. The economics that make counterfeiting a Rolex worthwhile do not apply, and the copies that exist are generally loose homages rather than exact reproductions. Compare the geometry against published images from several angles; the difficulty of the form is doing the work.

De Bethune · DB28 · Ref. DB28

De Bethune blues titanium thermally, so the colour is an oxide layer grown on the metal rather than a paint or a PVD coating. Under magnification and raking light it has depth and slight variation, and it follows the surface topography; a painted or coated blue sits on top of the surface and is uniform. At an edge, a coating can chip to reveal metal beneath — a thermal blue cannot, because there is nothing beneath it but the same metal.

Seiko · King Seiko · Ref. 44-9990

The 44KS case is defined by flat polished surfaces meeting at sharp edges — the finishing technique Seiko now markets as Zaratsu. Polishing rounds those edges irreversibly. On this reference, case condition is not a cosmetic matter: a softened case has lost the characteristic the reference exists for, and it removes a comparison point an examiner would otherwise use.

Hamilton · Ventura · Ref. Ventura (1957 Electric)

The Arbib case has compound curves and a specific relationship between the two shield points and the lug line. Reproductions and re-cased watches get the proportion wrong more readily than they get the dial wrong, because a dial is a printing problem and this case is a tooling problem. Compare the point-to-point geometry and the depth of the dish, not the logo.

Tissot · PRX · Ref. T137.407.11.041.00

The automatic PRX is 10.9mm over a 40mm case, and the flat tonneau profile is the point of the design. Counterfeits built around a taller generic movement come out visibly thicker and lose the flatness the model exists for. Measure it: a PRX noticeably over 11mm is carrying a movement it should not.

Seiko · Tuna · Ref. 7549-7009

Titanium nitride is hard but not indestructible, and a working example will show wear at the shroud edges. A 7549 with a uniformly perfect gold shroud has most likely had it replaced or re-coated. Neither is a counterfeit finding on its own; both are originality findings that should be recorded rather than admired.

Jacques Bianchi Marseille · JB300 · Ref. JB300 Re-Edition

Like the JB200 the JB300 uses the left-hand crown at 9, but with a 300m case, toothed bezel and a date at 3 on a Maxi dial. Movement is the Swiss Soprod P024 (not the JB200's NH35).

Rado · DiaStar Original · Ref. R12161653

The material tests that authenticate a 1962 DiaStar will fail a genuine R12161653, because it is not made of the same thing. Establish the reference and its specified materials first. This is the most likely way for an examiner who knows the brand's reputation to reach a confidently wrong conclusion about a correct modern watch.

Hamilton · Ventura · Ref. Ventura (1957 Electric)

The most exposed edges of the case wear first and the base metal shows as a pink or grey line. On a gold-filled Ventura this is ordinary honest wear. What it also means is that a gold-filled example with sharp, unworn, uniformly bright points has either been re-plated or is not what it claims — check the case markings for the metal designation and see whether the wear pattern is consistent with them.

Hamilton · American-Era Named Wristwatch · Ref. Boulton

The curve means the case rides against the wrist along its edges, and honest wear shows as base metal along the flanks and at the caseback rim. Uniform brightness across a curved gold-filled case, with no wear at those points, indicates re-plating.

Tissot · Antimagnétique · Ref. Antimagnétique

Plated cases show base metal at the lugs and caseback rim, which is honest wear. Solid gold cases carry the hallmarks of their country of assay, and those hallmarks are the evidence for the metal claim — not the colour, and not a stamped fineness alone. Where hallmarks are absent on a case claimed as solid gold, the claim is unsupported.

Vostok · Komandirskie · Ref. Soviet MoD issue

Unlike the Amphibia, the classic Komandirskie is a thinner field case without the Amphibia compression-caseback/thick-acrylic sealing system. A 'Komandirskie' presented with Amphibia-level dive sealing is a configuration mismatch to investigate.

Jacques Bianchi Marseille · JB200 · Ref. JB200 (1982)

Both the vintage and modern JB200 use an elongated tonneau case with prominent crown guards and the crown on the LEFT side at 9 o'clock. This destro layout is the single strongest identifying feature of the model; a right-crown case is not a JB200.

Jacques Bianchi Marseille · JB200 · Ref. JB200 Re-Edition

Both the vintage and modern JB200 use an elongated tonneau case with prominent crown guards and the crown on the LEFT side at 9 o'clock. This destro layout is the single strongest identifying feature of the model; a right-crown case is not a JB200.

TAG Heuer · Monaco · Ref. 1133B

The original automatic Monaco places the winding crown at 9 o'clock (the manual re-editions moved it to 3). Crown position must match the movement.

Franck Muller · Cintrée Curvex · Ref. Cintrée Curvex

The compound curvature is the single most reliable check on the brand. A genuine Cintrée Curvex curves along its length and across its width, and the sapphire crystal is curved to match — which is expensive, because a doubly curved sapphire is a difficult component. Counterfeits routinely produce a case curved in one plane with a flat or singly curved crystal. Viewed from directly above, in the photograph a seller supplies, this looks broadly correct; viewed from the side it does not. Insist on a profile view.

Hamilton · Khaki Field · Ref. H69439931

The case is delivered bead-blasted. A Khaki Field Mechanical with bright, reflective flanks has been polished after leaving the factory. That is an originality finding rather than an authenticity one, but it also removes the crispness of the case edges that would otherwise help judge it.

Rolex · Sea-Dweller · Ref. 1665

Vintage Sea-Dwellers omit the date Cyclops for pressure integrity; a Cyclops on a 1665 is incorrect.

Seiko · Chronograph 6138 · Ref. 6138-8020

The gold-tone execution is plated, not solid, and wear through to the base metal on the high points is normal for the age. A gold-tone 6138-8020 with uniformly perfect plating has most likely been re-plated — which softens the case edges and is worth noting, but is a condition and originality matter rather than an authenticity one.

Rolex · GMT-Master · Ref. 1675

Earliest 1675 cases have pointed crown guards; these transition to rounded guards. A rounded-guard case wearing an early serial/dial is suspect.

Seiko · Willard / Captain Willard · Ref. 6105-8110

The -8110 case has defined flat surfaces and a sharp transition into the crown guard. Heavy polishing rounds these and thins the lugs, which is a condition finding of real consequence on this reference specifically — a heavily polished example can no longer be compared against reference geometry, so several other checks become unavailable at the same time.

Universal Genève · Compax · Ref. 885103

A heavily polished case has lost its original edges, its lug proportions and often much of its reference and serial stamping. Since the archive cannot be consulted, that stamping is a significant part of the available evidence, and its loss narrows what can be established. An unpolished example is dramatically easier to authenticate and is priced accordingly — which is itself a reason to look closely at any case presented as unpolished.

Chanel · J12 · Ref. J12 Calibre 12.1

Ceramic is very hard and comparatively brittle: it should show no fine scratch haze after years of wear, and it chips or cracks under impact where steel would dent. An examiner trained on steel reads scratches as ordinary wear and a chip as abuse, and on ceramic that inference is exactly backwards. A scuffed J12 case is a material finding; a chipped one is merely damaged — and the chip is corroboration that the material is real.

Baume & Mercier · Hampton · Ref. Hampton

The relationship between case length, width and the curvature over the wrist is what makes a Hampton look like one. Where a rectangular watch is in question, measure rather than compare by eye — the human eye is poor at judging aspect ratios and good at recognising familiarity, which is exactly the wrong combination.

Hamilton · American-Era Named Wristwatch · Ref. Piping Rock

Because a genuine 14k case is the expensive part, reproduction cases exist and are fitted with genuine period Hamilton movements. Check the case hallmarks and the case-maker's marks inside the back against period practice, and check the fit of the movement in the case: period cases were made for the specific movement and a modern case is usually a shade generous.

Jaeger-LeCoultre · Reverso Classic · Ref. Q2548440

The Reverso's rectangular case slides and flips within its cradle to protect the crystal — originally for polo. The swivel action, the cradle rivets and the caseback's crisp Art-Deco gadroons should be precise and smooth.

Jaeger-LeCoultre · Reverso Tribute · Ref. Q3978480

The Reverso's rectangular case slides and flips within its cradle to protect the crystal — originally for polo. The swivel action, the cradle rivets and the caseback's crisp Art-Deco gadroons should be precise and smooth.

Rolex · Explorer II · Ref. 226570

The 226570 keeps 42mm but slims the lugs/case profile relative to the 216570 'Maxi' — the key visual differentiator between the two 42mm generations.

Seiko · Willard / Captain Willard · Ref. 6105-8000

The -8000 case is symmetric; the asymmetric, crown-guarded profile that the Willard nickname describes belongs to the -8110 and -8119. Listings frequently apply the nickname to both. Identify by the case shape and the caseback number, not by the seller's title.