During the late Eastern Zhou period, 6th-3rd century BC, various inlays were sometimes used to decorate bronze vessels. These inlays included copper, silver, gold, turquoise and a black matrix, which is seen on the present hu where it fills the decoration. This kind of inlay can also be seen on two vessels of Warring States date illustrated by Jenny So, Eastern Zhou Ritual Bronzes from the Arthur M. Sackler Collections, vol. III, The Arthur M. Sackler Foundation, 1995: one a faceted hu with burnished copper inlays in a ground of black matrix, pp. 261-62, no. 45; the other a stemmed fang hu from Shanxi Taiyuan Jinshengcun M251, p. 263, fig. 45.5. A black matrix inlay can be found on bronze vessels as early as the Shang dynasty.