An indication is called jumping when it advances in discrete jumps rather than with continuous motion. The distinction is mechanical before it is aesthetic: a disc, a hand or a cylinder accumulates energy in the movement, then releases it all at a precise instant. The eye reads the value without ambiguity, without having to interpret a hand halfway through its travel.
Jumping hours are the most widespread variant. A numbered disc rotates behind the dial window and jumps forward exactly one hour as the 60th minute strikes. The mechanism typically uses a cam spring that charges progressively and discharges suddenly: the finer the watch, the cleaner and quieter the jump. The window can be rectangular, octagonal, circular — the shape changes the character of the dial but not the principle. Some makers, such as MB&F on the HM8 or Hautlence on the Kubera, add prisms or sapphire prisms to enlarge and project the figure; the complexity increases but the concept remains the same.
Jumping seconds — also called dead-beat seconds or, in English, quartz seconds — make the seconds hand jump once per second, visually imitating the motion of a quartz movement while remaining mechanical. The distinction between jumping seconds and dead-beat seconds found online is essentially meaningless: it is the same effect achieved through different geometries, sometimes two wheels embracing a pivot with an intermediate lever, sometimes a patented mechanism as in the Arnold & Son DSTB, where everything is positioned on the dial side rather than on the back bridge.
Jumping minutes exist in two different contexts. In chronographs, the minute counter jumps forward exactly one minute when the seconds hand completes its revolution: this is achieved through a wolf's tooth wheel, making the reading of the measured time immediate. In digital or disc displays, as in the Lange Zeitwerk, the minutes jump on three simultaneous discs — hours, tens of minutes, units of minutes — at the start of every hour: a mechanically demanding moment because the accumulated energy must move several masses together without phase errors.
From the bench I have seen, over time, many poorly regulated jumping mechanisms: the jump occurs but the figure stops halfway across the window, or the spring discharges too early and the hour changes ahead of time. These are calibration faults, not design faults. A well-regulated jumping mechanism leaves no doubt: it is either still or it has already changed.
