Knife money was a form of ancient Chinese bronze currency shaped like knives and used mainly during the Zhou period and later regional states.
The coins probably developed from practical bronze knives or from miniature versions of tools used in exchange. Their blades and handles were cast together, and many examples carried inscriptions identifying a place, authority, or denomination.
Knife money was not uniform across China. Different states produced distinct shapes and inscriptions, including the large knife coins associated with the state of Qi. Their use illustrates that early Chinese money did not begin with round coins alone.
Knife money is often confused with spade money, another tool-shaped Chinese currency. Ban Liang and Wu Zhu were later round coins with square holes, associated with the Qin and Han monetary systems respectively.