The Patek Philippe reference 3970 perpetual calendar chronograph is considered a modern classic. The third iteration of the celebrated perpetual chronograph line of timepieces from Patek Philippe, the 3970 is the heir to the 2499, with which it shares the unmistakable case construction characterized by its sculpted lugs. Also, the 3970 replaces the Valjoux caliber of its predecessors with a Lemania caliber.
Beyond being aesthetically pleasing, the new indicators are extremely practical: the 24-hour indication allows the wearer to avoid setting the calendar when the time is around midnight and the calendar gear train is working, which would damage the movement. The leap-year indicator is invaluable when setting the perpetual calendar. Another practical addition is the push-piece for setting the month — previously one could only proceed one day at a time.
The 3970 represents the first ‘production era’ perpetual chronograph from Patek Philippe, and the fact that significant numbers of this reference were made relative to the 1518 and 2499 makes the 3970 more accessible in terms of price point and of exceptional value.
This particular example has a well preserved platinum case with crisp outside hallmarks on two of the lugs, a screw down sapphire case back, and a black dial with diamond hour markers, all confirmed on the archive.
The Certificate of Origin further confirming the originality of the black diamond dial is from 1996 also remains open and as it was never completed by the retailers.