In 2012, Patek Philippe replaced the ref. 5004 with the new ref. 5204. Another breakthrough for the firm, the new reference features Patek Philippe’s first in-house perpetual calendar split seconds chronograph cal. CHR 29-535 PS Q. Differing from the ref. 5004, the new model also features an enlarged 40mm diameter case compared to 36mm previously. While retaining similar aesthetics, the ref. 5204 featured some minor changes on the layout of the dial to enhance its legibility. One of the more noticeable adjustments was the implementation of an upside moon phase at 6 o’clock as well as two apertures indicating day and night as well as leap years. An experienced eye may also notice that the date registers no longer overlaps the outer minute track as it was the case for the ref. 5004 and it now features what collectors refer to as the “chin” allowing the date registers to sit above the outer minute track.

Ref Variations: 5204P-010,5204P-011,5204R-001,5204R,5204P,5204-1r-001,