Patek Philippe Annual Calendar Moonphase

Overall Condition: Excellent condition overall. Case shows only light wear and strong geometry. Dial and handset are in excellent condition. Factory strap and deployant show only light signs of wear.

In 1991, the soon-to-be graduates at the Geneva School of Engineering were presented with their final project prior to receiving their diploma — simplify the perpetual calendar.

Although the task was easier said than done, their work led to the inception of the annual calendar complication, patented by Patek in collaboration with the bright engineering minds at the GSE. Five years later, Patek debuted the Reference 5035 which marked the world’s first-ever annual calendar movement and finally bridged the gap between a triple date function and the formidable quantième perpétuel.

This piece, a Reference 5146P-001, is housed in a beautifully proportioned 39mm platinum case with a sapphire crystal, signed crown, and a smooth polished bezel. It features a luminous sunburst grey dial with applied indices, recessed subsidiary registers indicating day and month, a moonphase aperture and date window at 6 o'clock, and a matching luminous 'feuille' handset.

Powered by Patek Philippe's Calibre 315 S IRM QA LU automatic winding movement, it comes fitted to a signed black alligator strap with a signed platinum deployant clasp and includes its complete factory goodies.

This piece packs pedigree, refinement, function and outstanding craftsmanship that can only be expected on Patek Philippe.

Any old wristwatch can tell the time. Few truly define it.