Complication guide
Date and day-date: how the complication works
A date complication shows the calendar date through an aperture; a day-date adds the day of the week, usually in a second window.
The date is the most common complication of all. A toothed disc numbered 1 to 31 sits under the dial and is pushed on one step around midnight by the movement's calendar works. The chosen number shows through a small window, its position on the dial fixed by where the movement places the disc.
Because the date aperture is cut into the dial at a set point, a donor movement must put the date in the same place as the original. Two movements can share a diameter and height and still not interchange if one shows the date at 3 and the other at 6, or if one has a day window the dial has no aperture for.
Related complications and calibers
ChronographA chronograph is a watch with a built-in stopwatch, started, stopped a
Automatic windingAn automatic, or self-winding, movement winds its own mainspring from
GMT and second time zoneA GMT watch shows a second time zone on an extra hand that circles the
MoonphaseA moonphase complication shows the current phase of the moon through a
ETA 2836-2caliber and drop-in group
Sellita SW220-1caliber and drop-in group
ETA 2824-2caliber and drop-in group
All complications and typesBrowse every guide