Patek Philippe Perpetual Calendar 5940J Silver (5940J-001)

Exterior:
Do we need reminding that it was that the stunning design of this Nautilus was born in the brilliant mind of Gerald Genta? The star designer of the 1970s dreamed up the lines of this reference with the same undeniable mastery which led him to create a number of models that are still on the catalog of several prestige brands and indeed remain firmly in the design vanguard 40 years on. The development department therefore has only to adapt the dimensions of the case to the evolution of the movements and functions that have been introduced since.
The aptly named Nautilus was inspired by Captain Nemo's legendary submarine and the design of its bezel evokes a hatch capable of resisting tremendous pressure (12 bar like the original model). While purists will regret the appearance of a screw-in caseback fitted with a sapphire crystal, the Nautilus continues to flaunt perfect proportions, a modest thickness given its water resistance, as well as a comfortable fit on the wrist.
The dial also bears the original 1976 design and boasts exemplary finishes including gold hour-markers and a "chocolate" color that is one of the rare new features of this model.

Movement:
The self-winding 324 SC caliber with central seconds and disk- type date display is not the one powering the original model, but has nonetheless been part of the brand catalog for several years. The going train and automatic winding system, traditionally built and extensively tried and tested by Patek Philippe, springs no surprises other than renewed admiration for its exemplary finishes. Nonetheless, although entirely in keeping with the rules of the art, there is nothing ostentatious about the Côtes de Geneve, circular graining and beveling of the steel parts and bridges. The famous "Geneva" quality is omnipresent in an understated expression that would doubtless have met with Calvin's approval, yet which nonetheless betrays clear signs of industrialization.
Certain technological innovations developed in recent years by the Patek Philippe research laboratory are present in this movement, although they remain invisible to an untrained eye and are mostly concentrated on the escapement and the regulating organ: a four-arm Gyromax® balance-wheel and its inertia blocks serving to achieve dynamic fine adjustments, as well as the Spiromax® balance-spring in Silinvar® powering the sprung balance oscillating at 28,800 vph. While we do not yet have the benefit of much hindsight regarding the aging of components stemming from these technologies, the improvement in chronometry (timing precision) is clearly evident. Caliber 324 SC bears the Patek Philippe Seal characterized by some of the narrowest possible timing-adjustment tolerances.

Tests:
A string of figures could not possibly sum up the chronometric performance of this movement so vividly as the sense of precision it almost "metaphysically" exudes. As far as rates are concerned, the Patek Philippe demands a rate accuracy of between -3 and +5 seconds per day! While the amplitudes are not excessive and there is thus not much risk of knocking, they remained in any case superior to 255° in all the states measured. The high inertia of the balance-wheel doubtless plays a significant role in these results. As far as the power reserve is concerned, our measurements showed 38 hours, right in the middle of the range announced on the technical specifications. The performance of the automatic winding system is remarkable and the 21K gold oscillating weight ideally enhances the efficiency of the reduction gear train.

Conclusion:
This Nautilus fulfills the criteria one would expect from a model belonging to the sphere of Haute Horlogerie and appearing in the catalog of the brand. Given the magnificent developments introduced by Patek Philippe in recent years, one can well imagine that it will apply some of them to this iconic model, now that the monumental efforts devoted to its 175th anniversary are behind it. Surely a legitimate hope placed in a brand that has been defining the standards of excellence for many decades?