The day of the month, displayed in a window on a watch dial typically at the 3 o'clock or 6 o'clock position. Systems and concepts with an effect on the date change at midnight: Instantaneous: the date changes with a synchronised jump at midnight within a tolerance of 1/- 10 minutes. Semi-instantaneous: the date moves slowly from around 11.30pm, at midnight the date is still visible. The function concludes with a jump of the disc. Total duration is 45 to 60 min. Dragging: slow function, the date changes slowly, starting at around 11pm, at midnight the date is still visible and the function continues without the disc jumping. Total duration is 120 min.