This large head was originally part of an eight-foot-tall Buddha, probably that of Amida, creator of the Pure Land of the West. Made of cypress wood, it was lacquered in black and covered with gold leaf, traces of which remain. It bears the requisite characteristics of a Buddha: the crystal third eye emitting infinite light, the tight curls of hair, and the elongated ears.
The head of a Buddhist statue is by far its most important element: the power, meaning, and compassion of the Buddha is expressed through its face. The construction of this head is of an ancient type seen only in sculpture of the eleventh century or before, called wari-hagi-zukuri (splitting, carving out, and rejoining). In this technique the head is first carved from a single large block of wood, then split into halves along a vertical line behind the ears, creating a front half and back half.
Both of these halves are then hollowed out using a chisel, and the two halves rejoined. This technique produces a sculpture that is lighter and far less likely to crack due to dryness. (Robert Singer, Curator Japanese Art)