Technical terms: The crown
The crown of a watch is usually found on the right side of the case. With Opis watches, they like to be set a little further down, as we do with the Caesar golden in the picture below on the right.
The function of the crown can be very diverse. On the Caesar, it is used to start the watch (by pushing in), to stop it (by pulling it out) and to set the time (by turning it while pulled out). Opis watches with a calendar (for example the unisex watches from the Schillers Werke series such as the Tell , or the two-time zone watches Jakob and Fugger ) also have another pull-out position in which the date and not the time can be set.
Of course, the name comes from the sometimes more, sometimes less existing similarity to the royal crown.