Minute Repeaters and Chiming Watches Explained

A minute repeater is a watch that chimes the time when you slide or push a lever. It strikes the hours, then the quarter hours, then the minutes, using tiny hammers that hit gongs wound around the inside of the case.

The complication dates from before electric light, when a repeater let you find out the time in the dark without a flame. Today it is a showpiece of acoustic and mechanical engineering, and it is among the most difficult complications to make well.

When you activate the repeater, you also wind a dedicated spring that powers the chime. A set of snail-shaped cams, called snails, measure the hour, quarter and minute positions, so that the number of strikes matches the time shown. A governor controls the speed of the chime so it plays evenly.

The sound is the whole point. Makers spend years refining the case, the gongs and the hammers, because a beautiful clear tone matters more than loudness. Sapphire and gold cases and open case sides can change the sound significantly.

The simpler cousins are the grande and petite sonnerie, which chime automatically at set times, and the sonnerie au passage. They are even rarer, but they follow the same principle.

For most collectors a repeater is a collector's grail to admire in a boutique or museum. If you ever hear one in person, you will see why they hold their place at the top of watchmaking.