Retrograde date display
The retrograde date display shows the passing of the month with a date hand that moves in an arc from the 1st to the 31st of the month. After 31 days have passed, the spring is no longer under tension and allows the date hand to jump back to “one”. In months with fewer than 31 days or when the watch has not been used for a while, the date display can be advanced rapidly using the crown. This does not involve resetting the time.