The present watch, a stainless steel openface watch with one minute tourbillon regulator was manufactured in 1924, mounted in a yellow gold case bearing the case number 416638 and sold on October 22 1935. The watch was entered for the Geneva Astronomical Observatory for the timing contest on February 3 1931, where it was awarded the first prize.

The movement is Extra quality and stamped twice with the Geneva seal, and the movement number is signed twice as with all Observatory tested watches. The one minute tourbillon steel cage and central jewel carried in a gold screwed châton was fabricated by the celebrated watchmaking, James C. Pellaton (1873-1954). The sector dial is two-toned, and finished with black enamel batons and Arabic numerals, the outer minute track with subsidiary seconds.

This masterpiece is further accompanied by its original additional yellow gold case with hidden hinge, additional white enamel dial with Breguet numerals and spare blued steel hands.

There are many fascinating and historically important aspects about this watch. When held in one's hand, one can immediately marvel at its importance. The rarity is immediately enhanced when we realize that it is the only known stainless steel tourbillon still in private hands. The dial is in exceptionally well preserved condition. With its hard enamel printing and two-tone sector finish, the appreciation further extends to the collectors of Patek Philippe vintage wristwatches.

Perhaps the most important feature of this watch is that it was one of the only Observatory tested tourbillons to be fitted and sold in the same period of its testing. The majority of Observatory tourbillons are cased and sold some thirty, forty or even fifty years later.

The Patek Philippe Stainless Steel Observatory Tourbillon

Obtaining first prize in the Observatory testing in Geneva in 1931, the present watch is the only known stainless steel tourbillon in private hands. Only one other example of a stainless steel tourbillon is known and is on display at the Patek Philippe museum.

Exceptional quality, this tourbillon is further enhanced by the additional gold case, dial and hands which is prominently illustrated in Patek Philippe Stainless Steel Watches by the famed John Goldberger. Further distinguishing this incredible horological work of art, the watch was sold and cased very soon after testing, a mere four years. The majority of other tourbillon watches were tested, and the movement then remained with the firm for another 20, 30 or even 40 years and cased and sold decades after testing to their most prestigious clients.

The sector dial truly finishes this magnificent watch and opens the market not only to collectors of historically important pocket watches but will draw the attention of the most astute wristwatch collectors.