A focus on the PATEK PHILIPPE Grand Complication 3940 MK1 second series

The point of these " Focus " articles is to thoroughly explain, and sometimes from a comparative point of view, one generation of a specific timepiece model. In this article, we will be looking at the 3940.

The second generation of the 3940 is featured here, in its rarest and most rarely manufactured version, with a MK1 dial.

This perpetual calendar ref. 3940, which was highly appreciated by Philippe Stern and produced from 1985 to 2007, marked a whole generation of collectors and continues to be one of the "must haves" in the great Patek family today.

Vintage brochure illustration, shown here with a first generation dial

It was produced in three distinct series, with subtle variations, and has become a delight for connoisseurs who are proud to own different versions of the model, given that the subtleties are so important that they can make a significant difference in its intrinsic value.

To better understand the story behind the 3940, it is worth mentioning the legend that Philippe Stern, President and owner of the brand, was a marketing genius (or simply a visionary) for having launched, in a tense world economy and in a watch industry largely impacted by the Japanese quartz offensive, timepieces that resolutely went against the grain, such as the 3970 and 3940 model references.

Although model 3970 (which was the subject of a recent Focus) is a direct descendant of the 2499, model 3940 draws its legacy from several other sources of influence, but more importantly, it has its own distinctive identity, which is both elegant and discreet.

Image of a Perpetual Calendar Chronograph ref. 2499 (credit Sothebys) (©Sothebys)
Although it has a contained dial diameter, the size of its opening looks nice on the wrist

The perpetual calendar ref. 3940 second series was produced from 1987 to 1995 and is divided into two sub-series:
- MK1 : 1987 to 1989 (Produced 3 years)
- MK2 : 1989 to 1995 (Produced 7 years)

Comparative overview of the second generation Mark I

Dial layout:

Unlike the first generation, the days of the week and month are now displayed inside the sub-counters, offering a more balanced and richer dial rendering, without compromising on readability.

We can see that the Geneva accent is only found on the first series of 3940s

Image of the sub-counter of a first (left) and second generation (right) in English and in German

The calendars come in English, German, Italian and some rare examples in French.

One of the most noteworthy differences between the MK1 and MK2 second generation dials is how the leap years are seperated by a cross on the right sub-counter, found on the MK2 dial.

Image of the straight sub-counters, which distinguish the MK1 dial from the MK2 dial on the second generation 3940

The case:

Despite its numerous complications, the 3940's case is flat and elegant. This watchmaking prowess is partly due to the micro-rotor of the oscillating weight

The caliber:

The Manufacture caliber 240Q is a real watchmaking achievement, with its surprisingly fine finish and extreme slimness (only 2.53MM thick!). Originally developed nearly eight years before launching ref. 3940, it can also be found in the Ellipse collections.

Just for the record, Mr. Stern was warned several times by his watchmakers about adding a perpetual calendar module on such a thin caliber.... A bold move that paid off!

Image of the 240Q manufacture caliber

The caliber is the same on both first and second generation models before being upgraded slightly on third generation models

Image of legal hallmarks for precious metals, here on the left side of the case

The hallmarks on the side of the case of the first and second series give it a certain charm that reflects its craftsmanship. The very first cases were supplied by Favre & Perret SA, a historical manufacturer. These markings are found on the back of the lugs from the 3rd series.

The 3940 was produced in yellow gold, white gold, platinum and rose gold (from the second series).

First generations of the 3940 perpetual calendar were supplied with a solid case back. Patek Philippe fitted a few rare models with a sapphire case back under reference 3941. Later, at the end of the second series, Patek Philippe issued these references with both a solid case back and sapphire backs.

Image of case back


Early generations of 3940s came with a rather classic style pin buckle. Over time, collectors have come to notice two types of buckles. A first buckle with a very square style, then a second one with a more bevelled and angular style. It was not until around 1997 with the third series of 3940s that a folding clasp was introduced.

Example of the first generation buckle with a very sober style found on the 3940, this MK1 buckle is found on the first generation as well as on the second generation 3940
Two generations of pin buckles compared on the 3940

The folding buckle was introduced in the third generation

Image of the folding clasp on the third series

Our thoughts on ref. 3940

The 3940 is an icon in itself. For passionate collectors, there is interest in collecting each different series, in different alloys. We have chosen to introduce the second series Mark I, which did not completely mark the break with the first series ( especially since it is closer to the first series than to the second series Mark II), but which is very interesting due to its confidential aspect.

Summary table of Patek Philippe 3940 variations

SerieFirst SerieSecond SerieThird SerieFourth Serie
HallmarksOn the sideOn the sideOn lugsOn lugs
Strap ClaspArdillon MK1Ardillon MK1 & MK2Folding claspFolding clasp
Case backFullSolid + sapphire on latest productionsSolid + SapphireSolid + Sapphire
DialWith Geneva accentWithout accentWithout accentWithout accent
MatériauxYellow Gold, White Gold, PlatinumYellow Gold, White Gold, Platinum, then rose gold on the latest productionsYellow gold, white gold, platinum, rose goldYellow gold, white gold, platinum, rose gold
Oscillating weight markings22K + Calatrava Cross22K + Calatrava CrossCalatrava CrossCalatrava Cross
Sub-counter charactersWith serifWith serifWith serifWithout serif
Position du σ Swiss σLowLowLowHigh, aligned with timer circle

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