The Patek Philippe Ref. 3940 is considered to be one of the most important pieces in Patek’s modern history, as it was the first highly complicated serially produced timepiece with a perpetual calendar alongside the perpetual calendar chronograph Ref. 3970. When looked at in context, the 3940 is significant in the sense that when it was released in 1985, Switzerland was in turmoil. An economic crisis in the Swiss watchmaking industry set upon by the Quartz crisis (or revolution depending on how you look at it), mechanical watches, a significant driver of the Swiss economy, had on paper become redundant. As an indicator of the drastic times and the effects felt, the number of people working in the Swiss watch industry dwindled from 90,000 to around 28,000 in the space of 18 years.
During this time of uncertainty, Patek Philippe, then headed by Philippe Stern, surprisingly released the 3940 and 3970 as a pair. Big Swiss companies were not making complicated pieces at this time as the decline in the industry meant that there was no spare money for innovative investment but instead only enough to consolidate whatever market share they had left. To release a perpetual calendar and perpetual calendar chronograph at the same time, was certainly a bold move by Patek and the timing could not have been greater as the tide was slowly turning with people realizing the value of mechanical watches. This is partly because looking at a mechanical watch and its movement is a very relatable experience, where you can see how it works, and how it is all connected, unlike a quartz watch that is powered by an incomprehensible chipboard. Perhaps it has something to do with a universal appreciation we have for craftsmanship as a whole, but whatever it was, this watch is a significant bedrock as to how far Patek has come today despite the adversities it faced. It is no coincidence that Philippe Stern himself, despite being in the position to wear any and as many Patek Philippe watches as he wished, chose to wear a 3940 every day.
Stepping back from the contextual significance of the 3940, the watch in itself is a marvel both in its design and movement. Housing the fantastically finished in-house perpetual calendar caliber 240 Q, one of its defining aspects is the integrated off-center micro-rotor, allowing this incredibly complicated watch to come in at an unbelievably slim 9mm. In order to ensure that a rotor that small could power the watch, it was made in 22k gold, with the extra weight providing more force to wind the watch.
Making a perpetual calendar is no easy task, with 275 different parts and as a testament to this, at the time it was released, there were only two people in the manufacture allowed to make watches this complicated. Sure, a perpetual calendar does not enjoy the same status as a chronograph, despite being more difficult to manufacture, as it lacks the tactile experience. But for a watch to have a memory of 4 years, accounting for the days in every month including February and the leap year, involves a large measure of skill. Add a moon phase and a 24-hour clock on top and you start to understand the complexity of this.
The aesthetics of the watch is an exercise in restraint, a timeless design combining the need for legibility with a beautiful symmetry of subdials. It has a silver dial with gold-applied index markers and dauphine hands. Each sub-dial provides two sets of information, with the 3 o’clock sub-dial showing the leap year indicator and the day of the week, the 6 o’clock sub-dial showing the enamel moon phase and the day of the month, and finally the 9 o’clock sub-dial showing the 24-hour clock and the month. The sub-dials are systemized within concentric circles and in an obvious hierarchy, with the day, month, and date on the outer track of the sub-dial, with the less important leap year indicator, moon phase, and 24-hour clock inside it. A cool little quirk of these 3940s is in the 24-hour subsidiary dial. In what looks to be discoloration, the orange tint of the bottom half is actually a subtle indicator to show that it is nighttime.
The 36mm curved case sits proportionately elegant on the wrist and its ultra-slim profile completes what is perhaps one of the most understated and elegant timepieces.
The 3940 was made in yellow, rose, white gold, and platinum, with white perhaps being the most desirable and rarest. While the platinum example was the most expensive, more people opted for that as it was close to indistinguishable from the white gold version and seen as the superior metal. What makes the white gold version more desirable today in my opinion is that the platinum version only came with a solid case back while the white gold version came with a sapphire display back.
While it is true that the 3940 does not shout out, it is, for this reason, I love the watch so much. This idea that you can wear this watch with barely anyone noticing, but you yourself knowing you have something truly special on is very, very appealing to me. There is a real purity to the design where perfect symmetry was achieved, balancing both undeniable elegant aesthetics with a fantastic movement. It is no wonder this watch was in production from 1985-2006, one of the longest run in Patek’s history.
(Several years ago, I wrote about the Patek Philippe 3940 here (https://www.bexsonn.com/patek-philippe-3940/) and it was one of my most personal articles due to the fact that I myself own a piece, which was passed down to me by my father. This written description is from that article.)