Hobnail-on-Hobnail 15509 Audemars Piguet Ultra-Thin

This is not an integrated bracelet watch. It is a watch integrated by its finishing. By that, I mean this example has been carefully manufactured such that the dial, case, bracelet, and, hell, even the clasp are all a consistent hobnial texture. Guilloché is an art form all itself, but to see the technique appliied to such a large surface of the case is spellbinding. Executed in full yellow gold, this early 70s ultra-thin calatrava has style. And a lot of it.

Derivative watch design is the bane of my existence and the only way to eradicate it is to diversify our interests. This may not be a style you wish to own, it may not even be particularly attractive to you. However, as a deep-level watch enthusiast (for which you qualify if you are reading), one should be able to appreciate the effort and careful construction that went in to create this watch.

First, there is the 35mm C-shaped case. It sports polished sides if only to provide a margin of contrast to the extensive circular guilloché pattern, which wraps to the contours of its lugs. Then the dial is a full hobnail or Clous de Paris also, distinguished from traditional AP tapisserie for its lack of spacing between the square faceted ‘blocks’. Lastly, the thin yellow gold bracelet is constructed with that same texture. Someone had a lot of engine turning to do in 1970. This reference was powered by the K2120, an ultra-thin JLC 920 ébauche. That’s a serious engine and it was finished to an equally serious standard by AP. The result is an objectively elegant ultra-thin calatrava with a wrist presence totally distinct from anything else in the room, guaranteed. That is something to be celebrated.

This example is sporting the lightest of surface wear on its polished sides but, as far as I can tell, that precious guilloché is almost totally unmarked. Someone wore this but cared for it. Its movement was recently serviced and it comes from a well-regarded Japanese retailer sans box/papers.

Find this 15509 here from Eguchi Japan for ~10900 USD.