The jumping date in the ATUM Date relies on a complex system composed of the date switching ratchet, release lever, switching star, and the date ring with the bracket-style marker. The date ratchet consists of the wheel itself, a ring-shaped switching finger spring, and the switching finger. The switching finger can freely rotate on the wheel but is secured by the ring spring in a position that allows movements on both sides but always requires tensioning of the spring. The mechanism is powered by the hour wheel at a ratio of 2:1, so the ratchet wheel fully rotates anticlockwise once every 24 hours. The transmission ratio of the date marker mechanism is calibrated to 11.6°, so the increments of the date ring add up to a total of 31 days.
The date can be changed in either direction at any time while the movement continues to run. The separate setting crown at 10 o'clock allows the date to be easily corrected, for instance at the end of a month. Normally, this setting crown is not engaged, so inadvertent adjustments are prevented.
The classic shape of the ATUM Date’s display radiates masculine elegance in the variant with a champagne dial. The date numerals, the minute scale and the small second are brown and the hands are also annealed to a brown hue. The entire date display appears to be tone-in-tone, yet clearly stands out against the lighter date ring, while the markers in white gold form a contrast and match the case.