Date indications in their variety are the most common complications. The most popular ones are the analog indicator and the date indicator. The calendar function of a watch derives from its date indication.
Within calendar indicators it can be differentiated between these types: from the simple date indication, the indication of the date combined with the weekday to the additional indication of the month and the year. Watches with all these indicators are called full calendar watches or watches with a large calendar.
Dual time watches and world time watches
Dual time watches offer the possibility to indicate the time of one or several time zones, usually as a separate indicator or by a clearly marked, centralized hand. World time watches indicate local times of larger cities by separate indicators or by a bezel on the rim of the watch face, which can be adjusted to the preferred city.
Chronographs are watches that enable you to measure any time period; short term timers or stop watches in their broader sense. Thus, these watches are equipped with additional indicators to measure hours, minutes and seconds. Some movements even offer stop times of tenths of a second.
A regulator is a watch that only has a central minute indication on the watch face. Hours and seconds are indicated with decentralized small hands which are placed on auxiliary indicators. This arrangement of the hands allows a fast reading of the watch since different hands can never cover each other. This type of watch derives from the big wall clocks which were used by clock makers or served as chronometers for scientific purposes. This principle of the hand arrangement was later transferred to watches.
Power reserve indication
The power reserve indicates how long the wound movement of a mechanical watch keeps working without having to be moved or wound. From a technical point of view this implies the current stress state of the spring of an automatic movement – comparable with a fuel gauge in a car.
The name of the retrograde indicators derives from the movement that is made by the hand. This is often the case with second hands but also with other indicators such as the date indicator. Retrograde indicators are sometimes called jumping indicators. This expression derives from the jumping movement that is made by the indicator when it reaches the end of the scale.
The retrograph is a watch with two second hands sharing the minute indicator: Once the first second hand has counted the first 30 seconds it jumps back to the zero position and the other second hand counts the remaining 30 seconds.
Day/night and 24-hour indicators
Day and night indicators show whether it is day or night by a certain symbol. Oftentimes they are combined with a 24-hour indicator.
Moon phase indicator
Moon phase indicators imply the current moon phase, the length of which is called lunatum in watchmaking and lasts 29 ½ days. This period is known as lunation or synodic month in astronomy and indicates the time period between two new moons.
Repeaters and alarm watches
Repeaters are equipped with striking mechanisms that announce the time acoustically when a release is pressed. They are sometimes called watches with striking mechanisms. Alarm watches are equipped with a function that makes an acoustic signal at a set time.
The tourbillion (Engl.: whirlwind) is a special construction of mechanical watches, which is supposed to improve the accuracy by reducing the position and gravity errors. For this, the lever, the escape wheel and the balance wheel are assembled in a small case which rotates around its own axis resulting in a balance of the occurring position and gravity errors.