The Ban Liang was the first unified currency of the Chinese empire, first minted as early as 378 BCE and introduced by the first emperor Qin Shi Huang as China's first unified currency around 210 BC. It was round with a square hole in the middle. Before that date, a variety of coins were used in China, usually in the form of blades or other implements, though round coins with square holes were used by the State of Zhou before it was extinguished by Qin in 249 BCE.

Iron cash coins are a type of Chinese cash coin that were produced at various times during the monetary history of imperial China as well as in Japan and Vietnam. Iron cash coins were often produced in regions where the supply of copper was insufficient, or as a method of paying for high military expenditures at times of war, as well as for exports at times of trade deficits.