25668BA Audemars Piguet Perpetual Calendar Skeleton

The 25668 is the ultimate evolution of the 5548, produced from 1988 until 1993 to celebrate the resurgence of complicated mechanical watchmaking to Switzerland. 154 examples were made in 18k yellow gold. They're divided into two case types, an earlier extruded pusher and this later flat pusher. Arguably, this is the height of historic AP outside of Royal Oak production. It’s the Doré 3940 in AP format, a direct rival of the 43032 that has its quirks and charms. But, really, all three are perfect and represent a certain high-water mark of post-quartz ambition.

At launch in 1978, the Quantième Perpétuel was the thinnest perpetual calendar that had ever been made at 3.95mm. Its calibre 2120/2800 was developed in the throes of the quartz crisis in secret, by a team of three senior watchmakers (lead watchmaker Michel Rochat, founder of the technical department Daniel Golay, and head of service Wilfred Berney) who feared Audemars Piguet's budget would not allow for the development of complicated mechanical watchmaking. The three formed their own skunkworks and worked after-hours in secret unpaid. The calibre utilizes thoroughly reworked JLC 920 ébauche with its own calendar works. The result revived not just Audemars Piguet's complications, but all of Switzerland. Calibre 2120/2800 changed the course of watchmaking history. The 36mm case was then penned by Jacqueline Dimier, arguably her most famous work with its gracefully downturned lug and steeped bezel. 

This all gold aesthetic is the most produced but also one of the most lovely. But it is between the subdials where effort has been poured. First, the sword subdial hands are heat blued. The openworking encompasses hand engraving, bevelling, anglage, black polish, and an uncountable number of inner angles. The skeletonized moonphase is a particularly thoughtful touch. It is a celebration of traditional technique flourishing again in Switzerland. 

The 25668 is one of the most visually captivating of the Holy Trinity post-quartz perpetual calendars. To the extent that modern AP has become the Royal Oak company, they do immense disservice to this legacy, one of the greatest in watchmaking. This watch led the charge for mechanical watchmaking’s return against the growing quartz shadow and sold to great success. It is easily one of the most critical, significant references of the last century.

This is a great looking example. The case engravings are sharp, which you can always most clearly assess on the case engravings opposite the crown side. It comes with its buckle, but as watch only from a well-regarded Malaysian retailer.