The chronograph is of course the first of what are known as useful functions. But there are others such as the second time zone, universal time, power reserve or self-winding devices.
The time-zone is very convenient for long haul travellers who often experience time differences. The watch indicates simultaneously the time in the country where the traveller is currently located and the time in his country of origin.
Universal time watches permanently and automatically display the 24 time zones symbolised by the same number of cities across the world or even more. A 24 hour disc is located around the central dial while the disc on which the towns are named appears on the periphery. The city in which the user finds himself at any given time is positioned at 12 o’clock. This highly ingenious device enables the user to see at a glance the time in other parts of the globe. It also enables the time at the reference place to be adjusted easily and rapidly.
If complications are regarded solely as additional indications, self-winding is not one of them. However, it is an extremely useful device enabling the watch spring to be tensioned and hence wound up by movements of the wearer’s wrist.
The power reserve is often represented on the dial by a sector and shows how much longer the watch can still run before it needs to be wound again.