Satin-finish gold Tank à guichets watch
Instead of a hand, a "jumping display" uses numerals, seen through an aperture, which instantly change on the hour (or minute).
The circular motion of hands has been adopted by our societies as the most "natural" way to convey the passing of time, no doubt because it recalls the rotation of the planets and the apparent movement of the sun, our first timekeeper. There are, however, other ways to indicate time, such as a "jumping display", typically used to show the hour. It exchanges the hand for a disc inscribed with the hour numerals, and in this is visually similar to a calendar aperture. However, unlike certain calendars, each new indication is instantaneous. On each hour, the mechanism causes the disc to make one jump forward, then blocks it in this position until the following hour. Some watches also feature "jumping minutes", although jumping hours are more usually paired with retrograde minutes.
Jumping-hour mechanisms are now returning to favour. They open up a realm of possibilities for designers to demonstrate their inventiveness in boldly original dials. Jumping displays have recently been the object of spectacular developments, in particular with the arrival of highly complex three-dimensional systems.