Knife Money

Knife money (Chinese dao or daobi) is cast bronze money shaped like a small knife, with a curved or straight blade, a handle and a ring at the end. It was used in the eastern and north-eastern states of China during the later Zhou period, above all in Qi, Yan and Zhao, and circulated until the Qin unification of 221 BCE.

Like spade money, knife money began as a stylised version of a working tool. It is one of the distinctive regional forms of early Chinese money and shows how the states of the Warring States period each developed their own currency before a single imperial coin replaced them.

Small bronze knives were common everyday tools in northern China and among the peoples of the northern frontier. Where these knives were traded widely, they became a convenient medium of exchange, reducing the need for barter. Monetary knives were cast specifically for payment, and over time they lost any practical cutting edge while keeping the outline of the original tool.

Most surviving knife money dates from the Warring States period (475–221 BCE). Some types may be older, but firm dating of the earliest pieces remains uncertain.

• Qi knives: large, heavy pieces from the state of Qi in the Shandong region. Their inscriptions often include the name of the state and a term for money, and they are among the finest cast pieces of the period.
• Ming knives: smaller, lighter knives named after a character on the blade traditionally read as ming. They are associated mainly with the state of Yan in the north-east and were produced in very large numbers.
• Straight knives: narrow pieces with a straighter blade, linked with the state of Zhao and other northern areas.

Most knives have a ring at the end of the handle. The ring may have allowed pieces to be strung together, and some scholars see it as a link to the later round coin with a hole.

Knife money was cast in bronze using stone or clay moulds, several pieces at a time. Inscriptions were cut into the mould, so they appear raised on the finished piece. Because each state controlled its own foundries, sizes, weights and alloys varied between states and over time. Later Ming knives tend to be thinner and lighter than earlier ones, consistent with the gradual reduction in metal content seen in many systems of currency debasement.

Knife money served as the everyday currency of its home regions, used for trade, wages and payments to the state. Ming knives in particular have been found in large hoards across north-eastern China and beyond, including in the Korean peninsula, which shows that Yan money travelled along regional trade routes.

The monetary map of the Warring States period was mixed. Knife money dominated in the east and north-east, spade money in the central plains, cowrie-shaped bronze pieces in the south, and round huanqian spread across several states from the fourth century BCE. In the later Warring States period Qi and Yan themselves began casting round coins with square holes, so knife and round coins circulated side by side.

After unification in 221 BCE the Qin government adopted the round ban liang as the single bronze coin of the empire, and knife money was withdrawn from use. The shape returned briefly under Wang Mang, who issued knife-shaped pieces of high nominal value in the early first century CE. These were a form of token money worth far more than their metal, an early example of the gap between face value and intrinsic value that underlies modern fiat currency.

The long-term winner was the round coin with a square hole, standardised in the Han wu zhu and later in the kaiyuan tongbao. Knife money remains one of the most recognisable artefacts of early Chinese economic history and a popular collector's item. Together with spade money and cowrie shells, it illustrates how money in China evolved from objects with practical use towards abstract, state-issued coins.

• British Museum – Collection online
• American Numismatic Society