The Tischkalender which quite simply means desk calendar and, on the one hand, is exactly that: A work of art displaying the date. On the other hand, it is one of the most complex and astounding pieces of watchmaking since Breguet’s Montre Sympathique. Breguet invented a master clock which wound and set a pocket watch when the latter was connected to the former.

Andreas Strehler’s Tischkalender does something more complex: A pocket-watch displaying the time is inserted into the desk calendar unit which is, in fact, a perpetual calendar. Once the owner goes away from his desk, he takes the pocket watch with him. The desk calendar stops. Once the owner returns to his desk after some days or weeks, he inserts the pocket watch into the desk calendar. The desk calendar knows how long the owner was absent and sets the date right. It has a mechanical memory.

This complex mechanism is designed in a way which makes it virtually impossible to make an error in its operation. For example, only when the pocket watch is properly inserted does the synchronisation start. And only when the synchronisation is properly done can the pocket watch be removed. The winding mechanism disengages once the Tischkalender is fully wound. In 1997, Andreas decided to actually build the Tischkalender. The pocket watch was finished at the end of the same year.