Emperor Qin promulgated China's earliest Currency Act, which prescribed the nationwide use of the Qin State currency, called half-liang coin, circular and with a square hole in the center. According to the current information unearthed, the currency has the following characteristics: it weighs half-liang, equal to current 7.8 grams, with the diameter of over 3 cm and the character Qin Xiaozhuan (small seal script) carved on the coin, which is rather well made.

This act ended the chaotic state of China's ancient currencies, which were different in shape and weight, and thus moved forward in a major step in China's monetary history from messy shapes to a standard one. The shape, which is circular with a square hole, had been used until the early period of Republic of China.