When you own a luxury watch, you basically just want to know what time it is. But what if you want to get more out of it? What if you want more watch functions than just reading the time? Then you can buy a luxury watch with a so-called watch complication.
A complication is another function of your watch. The most common watch complication is the “date function”, because many people find it useful to know the date apart from reading the time.
The date can be shown in different ways, but the most common way is through an opening in the dial. There are also watches where the date, like the hour indexes, run along the edge of the watch. You can then read the date by means of an additional hand.
Another way in which the date can be shown is through a small subdial. On this small dial, the dates are displayed along the edge and can be read by a small hand.