Each additional function of a watch, beyond telling the time, is known as a complication. While every added complication requires extra levels of skill and craftsmanship from the watchmaker, their real purpose is to add information: they provide data and bring pleasure and fascination to the owner. Knowing how to read a complicated watch gives the wearer control over their environment.
Calendar indications can display the date, weekday and month, but they need resetting at the start of certain months. A perpetual calendar has been built to account for short months and leap years. It will automatically adjust to the first day of the new month, no matter whether the last month had 28, 29, 30 or 31 days.
A watch that strikes the hours, quarters and minutes. often activated either by a sliding piece or push button in the band, it acoustically indicates the correct time by means of hammer(s) striking one or several gongs.
The tourbillon was invented by A. L. breguet in 1801 to eliminate errors of rate due to gravity distorting the clockwork more in one direction than any other – as watches on the wrist tend to spend most of the time with either 12 or 3 pointing downwards. A tourbillon is a cage that carries all the parts of the escapement. The cage rotates once per minute around its centre, annulling errors of rate in the vertical positions.
A timepiece allowing its wearer to measure time intervals without influencing or pausing the main time indication. Usually, a chronograph is activated with a button and stopped with the same button or another. most commonly, chronographs measuring the seconds are mounted in the centre of the dial. In order to register time intervals with duration over 1 minute, chronographs are also often equipped with minute and hour registers.
A chronograph allowing its wearer to simultaneously measure several different events that start at the same time using an additional, superimposed, second hand. Pressing the split-second button stops the lower hand, while the upper hand continues to rotate around the dial. After taking a reading from the paused hand, pressing the button again snaps this “rattrapante” hand (rattraper = to catch up) back to join the upper hand. This can be repeated indefinitely. After the last measurement the two hands can be stopped together and returned to zero.
POWER RESERVE INDICATION
This provides a visual indication of the remaining energy in the main spring, constantly informing its wearer of the available power, and ensuring that they can re-wind the watch in good time.