Nautilus two-part case with lateral hinges

Probable

The Nautilus case is built in two parts joined at the sides by the projecting 'ears', rather than as a case body with a screwed or snapped back. The construction descends from a ship's porthole and is the model's structural signature: the octagonal bezel is clamped to the case by the lateral fittings, and the seal is achieved by that clamping rather than by a threaded back.

Part reference

Brand: Patek Philippe
Material: Steel, gold or platinum
Introduced: 1976
Identifying marks: The ears are integral to the case profile and finished continuously with it, not applied. The bezel-to-case joint is a fine, even line all the way round with no step. Brushed and polished surfaces meet in crisp boundaries; the polished chamfer along the bezel's octagonal edges is even in width and meets cleanly at each vertex.

Documented variations

Classification

FactoryDocumented as shipped from the factory for this reference and period.PeriodNot original to this watch, but correct for its production period.ServiceFitted by the manufacturer's own service network. Not a defect.AftermarketThird-party part. Affects originality, not authenticity.ModifiedGenuine parts in a configuration the factory did not sell. Affects originality and value, not authenticity.CounterfeitDeceptive reproduction intended to pass as genuine.UnknownEvidence on file does not settle the question.

Correct factory finishing
FactoryProbable
Whole production
Sharp transitions between brushed and polished surfaces and an even bezel chamfer. Where counterfeits fail most reliably, because the cost is hand labour rather than tooling — a fake can copy the shape far more cheaply than the finish.
Third-party polished case
AftermarketProbable
Whole production
Refinishing outside Patek softens the brushed-to-polished boundaries and rounds the chamfers and vertices. It is damage to originality and value and is NOT evidence of a counterfeit — but it removes the finishing as an authentication signal, which should be recorded because it weakens everything inferred afterwards.

Documented on these references

Patek Philippe 3700/1AFactory
Whole production
The original Nautilus. Fifty years of wear means finishing on an honest example is softened; distinguish wear from a third-party refinish, and both from a counterfeit.
Patek Philippe 5980/1A-001Factory
Whole production
Patek Philippe 5726/1A-014Factory
Whole production
Patek Philippe 5811/1G-001Factory
Whole production
Patek Philippe 5711/1A-010Factory
Whole production
Among the most counterfeited watches in existence. Examine the bezel chamfer and the brushed-to-polished transitions before anything else — that is where the cost of faking it lies.

Provenance of this record

Sources & Evidence

Secondary sourceCollector research

Patek collector research on reference suffixes, case makers and dial variants

Collector communities and specialist dealers

Accessed: 2026-08-18

Cited for

This referenceProbable

Secondary sourceAuction archive

Auction-house scholarship on Patek Philippe

Major auction houses and their watch departments

Accessed: 2026-08-18