25636BA 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 were released in 1984. But it was AP’s first attempt at a skeleton QP, or perhaps in AP-speak I should say openworked QP. It started a legacy that we all love: pre-leap year skeletonized Royal Oaks, amongst the greatest Royal Oaks made.

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.

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. Then came skeletonization. The first skeletonized ref. was the 25636. All those without leap year fall under this reference.

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. Long live the pre-leap year Royal Oak QP, even if the market isn’t where it should be right now.

This example appears fantastic from what I can see here. The case rocks. Its bracelet is said to have zero stretch. It has its original winding box and Extract of Archive, noting sale in 1987 and all numbers matching, from a well-regarded London retailer.