Patek Philippe’s reference 3970 was a new generation of the brand’s famed serialised perpetual calendar chronograph first released in 1941 with the reference 1518, and followed ten years later by the reference 2499. Launched in 1986, the new reference featured a similar aesthetic to its predecessors with pump-style pushers and down turned stepped lugs, however, the case diameter was reduced in size from 37.5mm to 36mm.

The wristwatch was upgraded with a heavily modified Lemania 2310 base caliber, CH 27-70 Q, replacing the former Valjoux movement. Additionally, the dial was redesigned to include both leap year and 24-hour indications - greatly increasing the practicality of the watch.



The model was originally launched with two reference numbers: 3970 and 3971, respectively denoting solid and glazed back. Beginning with serial number 875’000, the first 100 examples featured a snap on case back with applied gold sword indexes and feuille hands. The second series featured a screw-down, solid caseback making it waterproof (thus the addition of “E” for étanche, meaning “waterproof”) with the hallmarks stamped on the outside of the lugs. The third series, like the present example, eliminated the difference between solid and glazed back, instead offering both backs with the watch, thus dropping the ref. 3971.

The present example in platinum has a perfectly preserved black gloss dial with diamond indexes, arguably marking the pinnacle of elegance for this timepiece. Offered for the first time at public auction, the present model from 1997 is in excellent overall condition and accompanied by its original Certificate of Origin, presentation box, setting pin and ever so important additional solid case back.