The Da Vinci Perpetual Calendar Chronograph (Ref. IW392101/IW392103) is the first watch from IWC to combine the well-known mechanical chronograph with a perpetual moon phase display on a sub-dial in a new complication module. The moon phase is displayed by a disc, partly silver- or gold-plated, partly dark blue, which rotates to show the shadow of the earth and the waxing or waning moon below an aperture in the dial. In order to achieve this, IWC’s watchmakers had to design the in-house 89630 calibre that powers the perpetual calendar’s other functions: the date, month, day and four-digit year display.
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