It is no small feat to create an immediately recognizable design language like Daniel Roth has with his signature ellipsocurvex case shape, hands with pointed tips and dials with a horizontal or Clous de Paris guilloché patterns.

Roth’s perpetual calendar was conceived originally with Philippe Dufour – whose workshops were only a stone’s throw away from Roth’s Vallée de Joux ateliers. The goal was to create the world’s first instantaneous perpetual calendar whereby all the calendar functions would jump to the next increment at the same time at midnight.

However, due to the weight of the day and month discs the movement would require too much energy and this proved technically challenging and as such Roth retained the more classical “semi instantaneous” system for this watch.

The present example is a superb example of Roth's philosophy: technical prowess, perfect legibility and a strong design.