Buddhist sculpture produced in Japan during the Kamakura period (1185-1333) is often referred to as the "pinnacle" of religious statuary in Japan (I have my own thoughts, but I don't want to digress). Among the most prolific and well-known sculptors was Unkei, whose workshop produced the massive guardian deities at the south gate of Todaiji.

One of the most definitive features of a Kamakura period sculpture is the rock crystal eyes which seem to glitter with life. This was accomplished by smoothing crystal into a contact-like shape, then painting the iris and pupil in the convex of the (future) eye. White paper was placed behind the crystal to accomplish the "whites" and then the whole ensemble held in place with wooden pegs at the back of the eye sockets inside a hollow face.