In 1986, the nearly four-decade long reign of the reference 2499 perpetual calendar chronograph came to a close, as Patek Philippe replaced its Valjoux-based perpetual calendar chronograph reference with the Nouvelle Lemania-based references 3970 and 3971. Initially these references differed only in the configuration of their caseback; the 3970 possessed a solid snap-on caseback, and the 3971 a sapphire snap-on caseback. Very few 3971s with this sapphire snap-on caseback were made, as the snap-on casebacks were quickly replaced by screw-down casebacks. The 3971 was only produced for about five years before it was absorbed into the general 3970 line, which would remain a mainstay of Patek Philippe’s catalogue until its discontinuation in 2004.

This is an unusual evolution for any Patek Philippe model, and is indicative of the era in which the 3970 and 3971 came to be. In the wake of the Quartz Crisis, the coinciding identity crisis of many Swiss brands forced them to either pivot completely away from their previous lineage, or double down on their core values as purveyors of high horology. Patek interestingly decided to shrink the case size of the 3971 from the 2499/100, aligning it more with its grandfather reference 1518. While the output of the model was at the beginning relatively low and rumored to be difficult to sell, the reference caught on and production eventually ramped up. Consequently, early examples are much more scarce than later specimens.

The present 3971, in yellow gold, bears the rare combination of a first series dial and snap-on sapphire caseback. It is fresh-to-the-market, and marks the fifteenth example known to scholarship. It is unpolished, with its original certificate confirming the sapphire caseback, and dated 1990 when it was sold by German retailer Huber. It is one of the rarest variants of the first modern perpetual calendar chronograph produced by Patek Philippe, and has been widely under appreciated previously, except for those most discerning of collectors.