Haute Horlogerie
A Tribute to Eternity
Portugieser Eternal Calendar
An intricate mechanism, reaching further into the future than ever before – capturing the beauty of time and eternity.
A watch that precisely reproduces the Gregorian calendar’s complex rules, irregularities and exceptions – for thousands, even millions of years to come.
We are building on our comprehensive expertise in engineering mechanical calendars - and pushing the boundaries in watchmaking once again.
The Portugieser Eternal Calendar
IWC Schaffhausen’s first secular perpetual calendar automatically takes into account the Gregorian calendar’s leap year exception rules by skipping three leap years over 400 years. It also features a moon phase display with an accuracy of 45 million years.
Take a look what’s underneath the dial
Double Moon™ display
The Double Moon™ indication uses two superimposed discs to display the moon phase as seen from the Northern and Southern hemispheres on the dial.
Month cam
As in a regular perpetual calendar, the mechanical calendar program is based on a disc containing a four-year cycle with 48 months, in which three common years followed by a leap year.
400-year wheel
The 400-year wheel reflects the Gregorian calendar’s leap year exceptions. It completes just one revolution every four centuries and makes sure that the calendar skips three leap years over that period – an event that will take place in 2100 for the first time.
Moon Phase reduction gear
On its orbit around the Earth, the moon does not follow a daily rhythm. One complete cycle from new moon to new moon does not last 30 days, but 29 days, 12 hours, 44 minutes and 2.88 seconds. To display the moon phase on the dial of a watch, the duration of one calendar months must be reduced to one lunar cycle. This is achieved by placing a reduction gear between the base movement and the moon phase disc.