Patek Philippe Yellow Gold Perpetual Calendar Chronograph Ref. 3971, Second Series with Original Box and Papers

Born alongside the legendary reference 3970, the reference 3971 is its far scarcer sibling: a perpetual calendar chronograph of the same era and architecture, but distinguished by its display back configurationa detail that, in period, was far from standard and today signals a watch made for the collector who notices the margins. It is believed that fewer than 300 examples of the 3971 are believed to have been produced, making it one of the most rare references of Patek Philippes modern perpetual calendar chronograph lineage.

This example is a second-series 3971, the generation that introduced a screw-down caseback construction (the E era, emphasizing improved water-resistance relative to the earliest snap-back cases). In yellow gold and preserved in exceptional condition, the case is the headline here: the stepped, downturned lugs remain sharp and well-defined, with the kind of retained geometry that is increasingly difficult to find on watches of this era.

Even more compelling are the deep, prominent hallmarks stamped on the outer sides of the lugs. This hallmark placement is widely recognized as one of the most desirable (and vulnerable) traits seen on certain 3971s an unusual choice that was later abandoned, likely because its prone to being worn down through handling. When those stamps remain bold, its a signal collectors immediately understand. The dial is equally correct and equally important: a clean silver (opaline) dial paired with feuille (leaf) hands, a combination closely associated with early-series aesthetics and prized for the softer, more vintage-inflected profile it lends the watch on the wrist. The result is the rare balance that defines the best 3971s: technically modern, visually classical.

Offered with its original box and papers, noting a sale in 1990, this is the kind of complete, condition-forward second-series 3971 that rarely comes togethersharp case, correct dial, and the hallmark detail that elevates it from rare to genuinely special.