Hufu, Bronze Inlaid Gold Tiger-Shaped Amulet with Inscriptions, Warring States Period ('475-221 BC), , unearthed in Xi'an City in 1975.

Hufu is composed of two halves. The shape and inscriptions of the two halves are the same, and together they are a token for mobilizing troops used by Generals to make a military order. The two pieces are like lock and key, only when fitted together can actions be carried out.