A display caseback is a see-through panel in the back of a watch case, made of sapphire or mineral glass. It lets the wearer look at the movement. Brands tend to fit one when the movement is finely decorated, so that the work inside can be seen.
How is a display caseback made?
Part of the metal back is cut away and a window is fitted in its place. That window is often sapphire crystal, though mineral glass is also used. One glossary puts it simply: an exhibition caseback is a back with a clear window through which the movement can be seen. The window does not have to be round. Some brands try out other shapes and sizes. Early clear backs were made of plastic, which scratched easily. Makers later moved to glass and sapphire.
Where it comes from
Bovet was one of the first makers to use a display back. By the 1820s it was putting glass in the back of some watches made for the Chinese market. Wristwatches with clear backs were reported at the 1952 Basel Fair in the trade journal Eastern Jeweller and Watchmaker. They arrived at the same time as self-winding movements, which buyers wanted to see and show off. Even so, see-through backs stayed fairly uncommon through the 1950s and 1960s. They became widespread in the 1990s, when mechanical watches came back into favour.
Not to be confused with
In the 1950s, clear watch parts such as these backs were called ‘skeleton’. A ‘skeleton back’ then meant a see-through back. The word later changed its meaning. Today a skeleton watch is one with an open-worked movement, not simply a clear window in the case. When a 1950s source mentions a skeleton back, it refers to a transparent caseback, not to open-worked mechanics.
Which watches have a display caseback?
Watches from Omega, Longines and Audemars Piguet have one. Rolex is a well-known exception. It has very seldom fitted a display back, so the movement of a Rolex usually stays out of sight. Sports watches also tend to go without one, whatever the brand. On those, a closed back is the usual choice.
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