Haute horlogerie A to Z

Watch Complications Glossary: Tourbillon to Grande Sonnerie

In watchmaking, a complication is anything a watch does beyond telling hours, minutes and seconds. The most prestigious watches combine many of them, which is where words like grand complication and supercomplication come from.

This glossary explains the terms used across our watch pages, with an example of where you can see each one.

Close-up of a tourbillon cage with a gold balance wheel visible through a watch dial

A tourbillon cage close up: Guy Sie from Utrecht, Netherlands, CC BY-SA 2.0

Glossary

Term	What it means	Where to see it
Complication	Any function beyond hours, minutes and seconds	Every complicated watch
Tourbillon	Rotating cage for the balance and escapement that averages out gravity errors	Breguet, 1801; many haute horlogerie houses
Flying tourbillon	A tourbillon supported from one side only, so it seems to float	First designed by Alfred Helwig, 1920
Minute repeater	Chimes the time on demand: hours, quarters, then minutes	Grandmaster Chime, Henry Graves Supercomplication
Grande sonnerie	Strikes hours and quarters automatically as time passes	Grandmaster Chime
Petite sonnerie	Strikes the hours automatically, quarters more simply	Grand striking watches
Perpetual calendar	Shows date, day and month and allows for leap years with no correction until 2100	Patek Philippe grand complications
Chronograph	A built-in stopwatch started and stopped by pushers	Rolex Daytona
Split-seconds (rattrapante)	A chronograph with two seconds hands to time two events at once	Henry Graves Supercomplication
Tachymeter	Scale for working out average speed over a set distance	Rolex Daytona bezel
Moon phase	Shows the shape of the moon through its monthly cycle	Many dress and calendar watches
Equation of time	Difference between clock time and solar time through the year	Patek Philippe Calibre 89
Celestial chart	Rotating map of the night sky for a given place	Henry Graves Supercomplication (New York sky)
Power reserve indicator	Shows how much energy is left in the mainspring	Many hand-wound and automatic watches
Self-winding rotor	A swinging weight that winds the mainspring as the wrist moves	Rolex Perpetual rotor, 1931
Balance wheel	The oscillating wheel that divides time into equal beats	All mechanical watches
Escapement	Releases the gear train one step per beat of the balance	All mechanical watches
Chronometer	A watch tested and certified for high accuracy	Rolex, many Swiss makers

Quick questions

What is a grand complication?

A watch that combines several major complications, usually including a chiming function, a perpetual calendar and a chronograph. Makers use the term in slightly different ways.

Does a tourbillon make a wristwatch more accurate?

It was designed for pocket watches that stayed in one position for hours. In a wristwatch that moves constantly the benefit is smaller, so today it is valued mainly as a display of skill.

Why are chiming watches so rare?

Repeaters and sonneries need tiny hammers, gongs and many coordinating parts, and each watch must be tuned by ear. Few watchmakers specialise in them.

What is the most complicated watch ever made?

The title has moved over time. The Henry Graves Supercomplication held it for over 50 years with 24 complications, then Patek Philippe's Calibre 89 of 1989 had 33. Newer pieces from several makers have since claimed even more.

What is the difference between automatic and manual winding?

A manual watch is wound by turning the crown. An automatic, or self-winding, watch has a rotor that winds the mainspring as you move, a system Rolex made practical in 1931.

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