The Watch: Patek invented the annual calendar in 1996 and patented it. The mechanism knows the difference between 30 and 31 day months, so it only needs correcting once a year, at the end of February, without the cost and fragility of a full perpetual. The 5035 introduced it, the 5036 added a power reserve indicator, and in 2005 the 5146 took over the line and consolidated everything the complication had accumulated over its first decade.
The dial carries day, date, month, power reserve, and a moonphase across its lacquered enamel. Up close everything is painstakingly detailed, from the raised frame of paint around the date window to the thick outlines on the moonphase's stars.
The case is 39mm in 18k white gold at 11.2mm thick, with a satin-brushed bezel and downturned lugs.
Inside is the cal. 324 S IRM QA LU, 355 components, 36 jewels, 28,800 vph, roughly 45 hours of reserve. The designation is a parts list: S for center seconds, IRM for indication réserve de marche, QA for quantième annuel, LU for lune. The movement is visible through the sapphire caseback.
This example comes on its original strap and buckle in excellent condition. Watch only.
Condition: Excellent, see photos.
Includes: Watch only.
