The importance of the perpetual calendar chronograph in the history of Patek Philippe cannot be understated. Some of Patek Philippe’s most important references such as the 1518 and 2499 house the perpetual calendar chronograph. It is estimated that the reference 2499, produced from 1950 to 1985, was produced in rather modest quantities (349 examples).

The 3970 represented a turning point for grande complications at Patek Philippe, prior to this both references, 1518 and 2499 combined production stood at around 630 examples. Despite its rather long production, 1986-2004, the reference 3970 can be segmented into four different generations, this particular example ref. 3970E forms part of the second generation and is believed to have been produced in 1989 and sold the same year. The production span of the second generation is thought to have started in 1986 and eventually passed out in 1991. The addition of the E (étanche, French for waterproof)  in reference was largely due to the fact that the case was now waterproof. This was achieved by replacing the snap-on caseback  in favor of the screw-down caseback.

The second generation is similar to that of the first, with minor changes such as the lack of contrast between the sub-dials which is usually found in the first generation. This reference was made available in four metals, white gold, yellow gold, rose gold and platinum.  Our example features an 18-carat yellow gold case with deep and crisp hallmarks found on the outer lugs. 

Dial

The opaline silvered dial features baton-shaped yellow gold indexes.  The dual apertures found at 12 o’clock just above the ‘Patek Philippe Geneve’ are used for both the day and month. The sub-dial found at 3 o’clock is used for the 30-minute chronograph as well as the leap year indicator. At 9 o’clock the sub-dial is used for the 60-second counter and a day-night indicator. The day and moon phase indicators are found at 6 o’clock. The overall aesthetic of the 3970 oozes elegance and the lack of a tachymeter allows for an undisturbed view of the dial. The 36mm case wears well due to its elongated lugs as well as the heft of the watch. There are four external pushers found on the periphery of the case, these can be used to set the complication.

The overall condition of the dial remains in excellent condition, the sapphire glass does feature a slight mark. 

Movement

This second-generation Patek Philippe 3970E is powered by calibre CH27-70Q. This very reference also signified the transition from Valjoux based movements to Lemania based movements. The marked the first lemania movement to be found in a Patek Philippe wristwatch, the iconic calibre 2320. Patek Philippe completely modified the movement by adding the perpetual calendar module. The movement is finished to a high standard and features different finishing techniques throughout the calibre.

The case number mentioned in the extract is 2.860.4XX, as well as the movement number 875.4XX both, correspond with the serial numbers found inside the watch. The 18 -carat gold pin buckle found on this particular example features a spelling error ‘Patek Phillipe’ instead of the usual ‘Patek Philippe’ 

Brand: Patek Philippe
Model: 3970E
Movement: CH27-70Q
Case Diameter: 36mm / Yellow Gold
Year: 1989
Box and Papers: Extract  dated 2020, original box and pusher. 

The importance of the perpetual calendar chronograph in the history of Patek Philippe cannot be understated. Some of Patek Philippe’s most important references such as the 1518 and 2499 house the perpetual calendar chronograph. It is estimated that the reference 2499, produced from 1950 to 1985, was produced in rather modest quantities (349 examples).