Annual date mechanism for clock movement

An annual date mechanism for a clock movement comprising a date indicating runner with thirty-one positions engaged once a day with a drive runner in kinematic connection with the geartrain of said clock movement, an annual cam, the contour of which is shaped to distinguish the thirty-one-day months from the other months, means for driving this annual cam by one revolution per year and a correction mechanism connected to said annual cam to advance said indicating runner by one additional position at the end of each month of less than 31 days, wherein the correction mechanism comprises a correction cam in kinematic connection with said date indicating runner, a correction rocker engaged, on the one hand, with said correction cam and, on the other hand, with said annual cam, and a spring for pressing said correction rocker against said cams, said correction cam comprising a portion for arming said spring, followed by a portion sized to cause said date runner to move by one step between the “31” and the “1” under the pressure of said spring.