Open Face in 18ct Two-Tone Gold

The case is the first uncommon thing: 18ct gold in two colours, the body in white gold, the bezel ring in yellow, a configuration Patek Philippe produced sparingly around 1931 and one that survives even more rarely with the contrast fully preserved. The brushed satin surfaces carry it well, and at 43.7mm the watch sits in the hand at exactly the scale the Art Deco years favoured: neither grand nor slight.

The second uncommon thing is engraved on the movement bridge: Brock and Company. George Brock opened his jewellery house in Los Angeles in 1903, and over six decades it became the city's foremost jeweller, the address where the film industry bought its serious pieces and an authorised Patek Philippe retailer trusted to put its own name beside Geneva's. The shop closed in 1964, which makes Brock-signed Patek movements a closed chapter: the ones that exist are all there will ever be.

The silvered dial is original and carries more detail than a first glance suggests. The numerals are stylised Breguet figures in the Art Deco cut, and each has aged to its own colour, copper on the eight, plum on the seven, violet on the three, the mottled toning that only develops when gilt is never touched. The hands are the matching Breguet pattern with the open ring near the tip, the minute track is a ring of raised pearl dots, and the sub-seconds register at six has an engine-turned centre. The signature reads Geneva, Switzerland in English rather than Genève, the export form for the American market, which fits the Brock and Company bridge exactly. Nothing has been repainted or restored. It winds, sets and runs well.

The marks, the movement and the condition are set out piece by piece in the drawers below; the retailer signature, the serials and the accompanying pouch and chain are recorded in The Record.