25636PT Audemars Piguet Royal Oak Perpetual Calendar Skeleton

This, Audemars Piguet’s 1986 ref. 25636, is the first AP skeletonized perpetual calendar of any sort. It was released in 1986, a full two years ahead of the 36mm ref. 25668 skeleton in a circular case. It’s not the first-ever skeleton QP, VC’s 43032 was released in 1984. But it was AP’s first attempt at a skeleton QP, or perhaps in AP-speak I should say openworked QP. Ceasing in 1996, it is the 9mm thin complicated razor. It started a legacy that we all love: pre-leap year skeletonized Royal Oaks, amongst the greatest Royal Oaks made.

Photography for this Find comes via prior sales by both A Collected Man and Phillips. 

Of this first series, AP Chronicle state archives show that 313 examples were made, with production ending in 1997. 156 in yellow gold, 41 in platinum, 61 in steel, 6 in pink gold, 24 in RP and PR (pink gold/platinum bimetal), and 25 in steel/platinum bimetal. And—here’s a deep cut—there’s also the gem-set sister ref. 25659 (Google it, I dare you) exists for anyone who finds plain platinum insufficiently committed. It’s a JLC 920 ébauche, adapted from from the 5548, and is still the calibre that had to be developed in secret after-hours by a passionate few, as the watchmakers feared AP’s spending wouldn’t allow it. At launch, it was the world’s thinnest self-winding QP. Which meant the Royal Oak case could accept it and as such the greatest sporting complication of the 90s was born. The 5554 was first. Remember it wasn’t as simple as a calibre marriage, the team had to fit correctors around the bolts that run from the bezel through the case. Later came skeletonization. AP's openwork atelier in Le Brassus, run by Régis Meylan from 1974 straight through to 2018, needed roughly 200 hours to finish each movement.

This really is peak AP. Calibre 2120/2800 is deservingly one of the most famed in watches. The dial is sapphire and the bridges have been worked down to bones, engraved, beveled where appropriate, and brushed or polished. These pre-leap example lack the crosshair on the 12 subdial that most find adds a bit of busy-ness. They also sit a bit above the later examples, such as the 25829, value-wise. They are spectacular, romantic, and the best of a great era of watchmaking. And they sell above 300K CHF now. Not bad for a watch three guys started building on nights and weekends in the Vallée de Joux.

This example comes with a COA from AP, but not the full kit. It's coming up later at Sotheby's in good nick.