The Da Vinci Perpetual Calendar Chronograph is the brand’s first watch to combine the hour and minute counters with the moon phase in a single subdial. Achieving this called for a development of the IWC-manufactured 89630 calibre. A silver-plated or gold-plated disc depicts the full moon in all its glory. At the same time, the rounded, dark blue section of the disc – representing the earth’s shadow – rotates to show the waxing or waning moon.