Perpetual Calendar Split-Seconds Chronograph 5951P Black / Silver

In Context

At 37 mm it sits just under the modern norm — the band that suits the widest spread of wrists. The case back is open, so the movement is visible without taking the watch apart, and the sapphire crystal will resist everything short of deliberate abuse. Rated to 30 m, it is protected against rain and splashes and nothing beyond that.

The movement is hand-wound, so winding it becomes part of the day rather than something the watch does for you. 48 hours of reserve is enough to set it down on Friday evening and find it still running on Monday. At 21,600 vph the seconds hand advances 6 times a second, the slower and more audible rate of an older design.

5951P-001 is one of 2 executions of the 5951P base reference. Underneath they are the same watch; what separates this one is a black dial and a platinum case. Introduced in 2011. Beyond the time it carries a chronograph and a perpetual calendar.

Split-seconds monopusher chronograph. 60-minute counter. Perpetual calendar. Day, month, leap year and day/night indication displayed in apertures. Date indicated by hand. Moon phases. Small seconds. Diameter: 27.3 mm. Height: 7.3 mm. Number of parts: 476. Bridges: 12. Jewels: 31. Power reserve with the chronograph disengaged: min. 38 hours - max. 48 hours. Balance: Gyromax®. Vibrations/hour: 21 600 (3 Hz). Balance spring: Breguet. Hallmark: Patek Philippe Seal.

5 other watches in the library run the Patek Philippe CHR 27-525 PS Q.

Patek Philippe

Perpetual Calendar Split-Seconds Chronograph 5372 Platinum / Blue

5372P-001 · 38.3 mm

Patek Philippe

Perpetual Calendar Split-Seconds Chronograph 5373 Left-Hander Platinum / Grey

5373P-001 · 38.3 mm

Patek Philippe

Perpetual Calendar Split-Seconds Chronograph 5951/500P

5951/500P-001 · 37 mm

Patek Philippe

Perpetual Calendar Split-Seconds Chronograph 5951P Silver

5951P-012 · 37 mm