Date Window
A watch component, material or construction term describing Date Window.
Also known as: date aperture, calendar window, date display window
Definition
A date window is an aperture in the dial through which the current calendar date is displayed, usually from a numbered disc rotating beneath the dial. The opening is often at 3 or 6 o'clock but can appear elsewhere depending on the movement and design. The date may change gradually or jump rapidly around midnight, and some crystals add a magnifying lens above the aperture. The window itself is only the visible opening; the date mechanism and disc are separate components beneath it.
Why it matters
A date window adds everyday utility but affects dial symmetry and can constrain movement choice. Correct date alignment and changeover are also useful indicators when checking a watch's condition.