The invention relates to a date mechanism comprising date disks (1, 2), a date program block (3) driving the date disks (1, 2), a driving block (4) driving the calendar program block (3) and a motor unit (5) for actuating the drive unit (4). The date disks (1, 2) comprise a first disk of the lower units and a second disk of the superimposed upper units and free in rotation relative to one another and a third disk of the lower tens and a fourth disk of the tens superimposed and free in rotation relative to each other. The calendar program block (3) includes calendar program mobiles for actuating the date discs (1, 2), said calendar program mobiles being arranged to selectively mesh with the date discs (1, 2) so that the last calendar of a month is displayed by means of the third disc of the lower tens and the first disc lower units and the first calendar of the following month is displayed by means of the fourth disc of the upper tens and the second disc of the higher units, the change of date between two consecutive months being done by a single jump of the fourth disc of the upper tens and of the second disc of the higher units whatever the month. The mechanism may include a month motive (24) and a leap year management mechanism (26) arranged to cooperate with the drive block (4),
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