Chinese square-holed copper cash

Timeline

1. c. -221–1367Central Plains region · Central PlainsThe Qin banliang established the round-coin-with-square-hole form; from the Han through the Song and Yuan, era-name coins predominated, with minting systems and weight standards adjusted as dynasties changed, making the square-holed coin the core form of Chinese currency.
2. 1368–1644Ming dynasty territory · ChinaThe Hongwu Emperor minted Hongwu Tongbao, inaugurating the Ming coinage system; thereafter each emperor's era-name coins, together with paper notes and silver, formed a multi-layered monetary structure, with square-holed coins handling everyday folk transactions and small payments.
3. 1431–1440Beijing and Jiangnan market towns · BeijingXuande Tongbao coins remained widely circulated; during the Zhengtong era, border-defense and fiscal pressures made the joint use of copper cash and silver more common, and the square-holed coin remained the payment form common people knew best in markets and tax conversions.
4. 1900–1912China · ChinaIn the late Qing, machine-struck copper coins and paper notes spread, and traditional square-holed copper cash gradually left everyday circulation, ending a minting tradition of over two thousand years, leaving only collectible and archaeological value.