Catalogue entry no. 507 by Max Loehr:
507 Pair of Hinged Disks
Light greenish gray jade with marginal brown areas, a material typical of the jades from Chin-ts’un. The movable disks were carved from a single slab that must have been as thick as the hinge or, more precisely, of the shorter diameter of its oval. This fluted hinge connects the disks by way of the peripheral extensions of their lattice-like openwork. The design of the latticework on one disk differs from that on the other; similarly, the outer extensions at the opposite side of the disks have the shape of birds in one case, and that of vaguely defined animal heads in profile in the other. Both sides of each disk are decorated with relief curls of varying forms and sizes, arranged in a roughly concentric order rather than on a grid. Late Eastern Chou.