The perpetual calendar from IWC Schaffhausen was developed in the 1980s by the then head watchmaker Kurt Klaus. In 2003, the legendary complication was presented in the Portugieser collection for the first time. Since then, the Portugieser Perpetual Calendar has been a mainstay of the collection.
The IWC-typical Double MoonTM display shows the moon from the northern and southern hemispheres. Thanks to a special reduction gear, it only deviates from the moon’s actual orbit by one day after 577.7 years.






