QP/Perpetual Calendar (QP-Quanitiéme Perpetual)
Perpetual calendars are mechanisms that change the date at the end of each month taking into consideration mechanically the variation of days, including the 29th February in leap years. The only adjustments required are for the exceptional non-leap years, the following being in 2100 and 2400.
A classical QP dial, the month hand turns once in 4 years. (Bissextile=Leap year)
The majority of QP’s indicate day/date/month/year in sequence
Here the year hand turns once every two years. (L=Leap year)