Portugieser Eternal Calendar

IWC's Portugieser Eternal Calendar is remarkable in many respects, having a mechanical programme that takes it far into the future. In addition to recognising the different lengths of the months over a four-year cycle, it takes into account the Gregorian calendar’s complex leap-year exception rule, whereby only centurial years that can be divided by 400 are leap years. Accordingly, a newly engineered 400-years gear ensures that the calendar automatically skips three leap years over four centuries – an event which will next occur in 2100. In other words, it will accurately calculate leap years until 3999, as it has yet to be officially decided whether 4000 will be a leap year or not. Another superlative feature of this Portugieser Eternal Calendar is the extraordinarily precise moon phase display. Thanks to a reduction gear train using three intermediate wheels, the Double Moon™ display will deviate from the moon’s orbit by just one day after 45 million years. The Portugieser Eternal Calendar is presented in a 44.4mm platinum case framing a glass dial. It contains the IWC-manufactured 52640 calibre whose two barrels supply seven days of power reserve.