Cash (Chinese coin)
The cash or qian was a type of coin of China and the Sinosphere, used from the 4th century BC until the 20th century, characterised by their round outer shape and a square center hole (Chinese: 方穿; pinyin: fāng chuān; Jyutping: fong1 cyun1; Pe̍h-ōe-jī: hong-chhoan). Originally cast during the Warring States period, these coins continued to be used for the entirety of Imperial China.