The Portuguese Perpetual Calendar has just about everything you could possibly wish for: a perpetual calendar, a perpetual moon phase display, a window showing the year in four digits, a seven-day automatic movement with Pellaton winding system and a power reserve display. The view of the lunar phases is reminiscent of classical representations of the moon, whose waxing and waning is due to the presence of two semi-circles. This is the method chosen by watchmakers over the centuries to depict the "celestial arena" in gold. In view of the extra space available in the large movement, the moon phase wheels in the IWC perpetual calendar now have more teeth, making the mechanism one of the most accurate available. After 577.5 years, it will deviate by just one day from the moon's actual progress. It is a modern and elegant timepiece that can hardly be bettered. The case is two millimetres less in diameter than that of its predecessor, a small modification that makes a visible difference on the wearer's wrist.