When Patek Philippe launched the Ref. 5370P — P for platinum — in 2015, and later the Ref. 5370R in rose gold, it positioned the watch very clearly: this was the manufacture’s contemporary, pure split-seconds chronograph, without calendar, without repeater, without distraction.

On the wrist, the 5370 is all about proportion and clarity. The 41-millimetre case is thick enough to accommodate the movement and water-resistant yet shaped to sit comfortably, with sculpted lugs and a concave bezel that frames the dial. The dial itself, first in black grand feu enamel and later in deep blue and then brown for the 5370R, is a study in restraint: with applied Breguet numerals, feuille hands, twin recessed registers and a tachymeter scale that hugs the edge without overwhelming legibility.

The real story, though, lies behind the sapphire caseback. Ref. 5370 houses the calibre CHR 29-535 PS, a split-seconds evolution of the base CH 29-535 PS. Here, the six base patents (see cover story) are joined by an additional set of refinements for the rattrapante function, drawn from Patek Philippe’s experience with the 5004 and formalised in the development of the 5204.

In everyday terms, the wearer experiences a chronograph whose split-seconds operation feels uncannily smooth. Start, stop, split, rejoin and reset all occur without visible stutter or hand quiver, and without the subtle drop in balance amplitude that keen observers sometimes see in earlier rattrapantes. The drive train, tooth profiles and isolator work together to ensure that the chronograph behaves like a single-hand system until the very moment a split is requested.

The 5370 therefore functions as a kind of open textbook on Patek Philippe’s split-seconds thinking. It shows what the manufacture considers essential in a rattrapante: twin column wheels, a horizontal clutch for classical feel, a carefully engineered isolator, optimised tooth geometry and a level of hand-finished steelwork that transforms clamps and levers into decorative objects in their own right. It is also the emotional anchor of the contemporary split-seconds story. Where the 5204 and 5308 integrate the rattrapante into larger mechanical ensembles, the 5370 gives it centre stage.

This story was first seen as part of the WOW #82 Festive 2025 Issue

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