Patek Philippe Perpetual Calendar Chronograph 3970E

Patek Philippe Reference 3970E 'Transitional 2nd and 3rd Series' | A yellow gold perpetual calendar chronograph wristwatch with moon phases, leap year, and 24-hour indication, Circa 1990

Dial: silvered Caliber: cal. 27-70 Q mechanical, 24 jewels Movement number: 875'987 Case: 18k yellow gold, screw down sapphire crystal display case back Case number: 2'873'837 Closure: 18k yellow gold Patek Philippe buckle Size: 36 mm diameter Signed: case, dial, and movement Box: yes Papers: no Accessories: Patek Philippe presentation box with outer packaging, additional solid case back, and setting pinPatek Philippe’s reference 3970 was launched in 1986 as a replacement for the iconic reference 2499. While maintaining the signature aesthetics found in both reference 1518 and 2499 the reference 3970 used a Lemania based ebauch as opposed to the previous Valjoux movement. These models also had a leap year and 24 hour indication for the first time. The reference was produced in yellow gold, pink gold, white gold and platinum across a total of four series with production spanning over 19 years. It is estimated that throughout its course of production over 4,000 examples of the reference were produced. First series (1986–1988): Snap back case, feuille hands, and rectangular hour indexes. Only produced in yellow gold, with approximately 100 examples made. Second series (1987–1990): Solid screw-back case (“E – Étanche”), feuille hands, and baton indexes. Produced across all four metals, with roughly 450 examples in total. Third series (1989–1995): Solid screw-back case (“E – Étanche”) with an additional sapphire display back, baton hands, and faceted (lapidated) hour markers. Approximately 1,350 examples produced across all metals. Fourth series (1994–2004): Maintains the configuration of the third series, though the movement and case serial ranges change. From 1997 onward, a deployant clasp was introduced. Around 2,000 examples are estimated to have been produced. At first glance, the present lot appears to feature a third-series dial, evident in its pointed baton hands and faceted hour markers. Upon closer examination, however, a dot between “31” and “1” on the date track which is characteristic of first and second series dials, reveals a transitional nature. Moreover, both the case and movement numbers on this piece align with those of a second series watch. These transitional examples also have a two-tone coloring effect on the the 24-hour subdial, likely an intentional choice during production: the “nighttime” half is varnished a shade darker than the “daytime” portion. A similar example, sold in the April 24th 2025 Sotheby’s Hong Kong Important Watches I sale (lot 2273), shares the same transitional dial and bears the case number 2’873’815—only 22 numbers apart from the present watch. Offered directly from the original owner, this example is accompanied by its original presentation box, additional solid case back, and setting pin. A superb opportunity for the discerning Patek Philippe collector who values the nuance and subtle evolution of one of the manufacture’s most celebrated perpetual calendar chronographs.