25558BA Audemars Piguet Quantième Perpétuel Openwork

Many ask what the ultimate 90s QP really is. Many will say a Beyer or Saatchi 3940. The VC equivalent of ultra-desirable, low volume is the 43032 Skeleton, preferably with blue subdials. The Audemars Piguet equivalent is this. Audemars Piguet saved complicated mechanical watchmaking in 1978 with the reference 5548. This is the 25558, the first openwork (skeletonized) model of that very QP. It was made in 217 examples, 154 of which were this gold. The 25558 (and latter 25668) is the ultimate AP neo-vintage perpetual calendar, which I’d argue is slightly more significant for having created the category and given both VC and Patek the confidence to return to mechanical complication in the wake of the quartz crisis. Despite the fact that the brand has forgotten about it entirely for Spider Man, taking up YouTube, and Cybertruck look-a-likes.

What I most love about this movement is that it was developed in secret. AP’s top brass was investing heavily into quartz and it was feared that no budget for mechanical watchmaking would be present in a few years. A team of three senior watchmakers (lead watchmaker Michel Rochat, founder of technical department Daniel Golay, and head of service Wilfred Berney) with immense skill formed their own Skunkworks inside the company. It was deliberately kept secret, for fear of reprimand. Once the lights were turned off at the end of a long day, they would convene. Without AP’s consent and totally unpaid, the three designed late into the evening for years. The result was the world’s thinnest self wound perpetual calendar movement ever, the 3.95mm thin 2120/2800.

The openwork here was created once the 5548 had seen success a little over 5 years later. It’s the victory lap. You’ll find this earliest 25558 features a case with extruded pushers. The latter 25668 only differs slightly in case construction. The engraving, beveling, and angles in the movement will reward hours of louping. The skeleton moonphase is a nice touch too. Plus, this is a lesser-seen spec with silver subdials as opposed to gold. This calibre was the success that brought AP’s complicated movement making, and most of Switzerland’s, back from the dead (not the Royal Oak). 2120/2800 changed the course of watchmaking history. AP could stand to do more to honor this legacy today, it has just been left to the history books. Its insane development story and market success are proof of the massive difference just a few determined and skilled minds can make.

This example appears to be in great condition overall. The engravings show deep, crisp, and true. Its lugs are fully proportioned. The watch comes with its original box and gold setting pin from a well-regarded Genevan retailer.