The self-winding Calibre 3638 is endowed with a 7-day power reserve, despite the presence of 434 parts including 39 jewels. Its complexity stems as much from the number of indications to be displayed as from the irregular nature of their cycles. The hours, minutes and the Gregorian calendar are presented in the center. The counter at 12 o’clock indicates the double-hour numerals and symbols (24-hour cycle); while the one at 3 o’clock shows the elements and the celestial stems (10-year cycle). The month of the Chinese calendar (12-month cycle), its date (30-day cycle) and the leap month indicator appear at 9 o’clock, while a 12 o’clock aperture reveals the zodiac sign of the year in progress (12-year cycle); and the moon phases are displayed at 6 o’clock.