Zero-reset seconds is a complication that returns the seconds hand to zero when the crown is pulled. The seconds hand stops and moves back to the upright position. While the watch is being set, the seconds hand waits at a known starting point.
How does zero-reset seconds work?
In A. Lange & Söhne’s version, a rod acts on a heart-shaped cam. The cam is fixed to the seconds hand. When the crown is pulled, the rod works on the cam and the stopped hand moves back to the upright position at once. Glashütte Original’s Senator Chronometer reaches the same result. Pulling the crown stops the balance wheel. The small seconds hand then quickly returns to its zero mark. In both cases the hand is not left wherever it happened to stop. It goes back to zero.
Where it comes from
A. Lange & Söhne patented its Zero-Reset system. The brand used the feature in the Langematik of 1997, where it was called Sax-o-mat. In that watch, pulling the crown returns the seconds hand to zero. Lange later combined the idea with another mechanism. In 2014, the 1815 Tourbillon paired zero-reset with a way to stop the tourbillon.
Which watches have zero-reset seconds?
Watches from A. Lange & Söhne and Panerai have it. Glashütte Original uses it too, as in the Senator Chronometer. There it is paired with a minute detent. When the time is set, the minute hand moves in one-minute jumps rather than turning freely. With the seconds hand waiting at zero and the minute hand stepping from one mark to the next, both hands sit on exact positions while the watch is being set.
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