Patek Philippe’s split seconds chronograph production can be split (pun intended) into two divergent camps: those with a single button operating the chronograph mechanism through the crown and those with the traditional two-button layout. The first split seconds chronograph wristwatch produced by Patek Philippe came in 1923, with a Victorin Piguet-based ebauche housed in a yellow gold officer-style case. Subsequent split seconds chronographs produced in series had two buttons: the ref. 1436, ref. 1563, and the piece-unique ref. 2512. All these references are highly coveted by collectors to this day. Patek Philippe wouldn’t produce another split-seconds chronograph until 2005 - the ref. 5959. In very much Patek Philippe style, the all-new, in-house ultra-thin movement cal. CHR 27-525 PS sports a single-button architecture, harkening back to the very first split seconds chronographs made by them. This groundbreaking, fully in‑house movement was then the world’s thinnest split‑seconds and column‑wheel chronograph, embodying the manufacture’s mastery of complications.

At Baselworld in 2010, Patek Philippe announced ref. 5950, a cushion-style, single button split-seconds chronograph with the same in-house movement but boasting subtle Belle Époque styling. The model is a treasure trove of surprises, the most obvious one being the fact that it is a highly complicated Patek Philippe model in steel. Piling on this foundation, we can find traits that seem designed to delight the connoisseur: from the applied black gold Breguet numerals to the black lacquer scroll detailing at the corners and on the buckle, and even in the corners of the additional solid caseback. The dial surface features an opaline/ivory finish obviously reminiscent of vintage watches, a feeling boosted by the railway fifth-of-a-second divisions and Arabic (in fact using a Breguet font, another subtle detail highlighting the meticulous design process behind the model) five-minutes divisions.

Production of the ref. 5950A is believed to have been extremely limited as they were “application” pieces reserved for the brand’s most cherished clients. According to research, only 16 examples are known to the market. The present watch is “fresh-to-the-market”, making it the 17th example known. Preserved in exceptional condition and complete with its full set of accessories, including an additional solid caseback with the same styling found on the dial, movement and buckle, this watch is undeniably charming and exudes sophistication.

Complicated steel Patek Philippes are today regarded as “endgame” watches for collectors—the ref. 5950A is easily a category of its own and one of the most compelling creations of modern Patek Philippe. It’s no wonder that Mr. Goldberger chose this reference as the cover illustration for his seminal book Patek Philippe Steel Watches.