Kaiyuan Tongbao
The Kaiyuan Tongbao (traditional Chinese: 開元通寶; simplified Chinese: 开元通宝; pinyin: kāiyuán tōng bǎo; lit. 'Circulating treasure from the inauguration of a new epoch'), sometimes romanised as Kai Yuan Tong Bao or using the archaic Wade-Giles spelling K'ai Yuan T'ung Pao, was a Tang dynasty cash coin that was produced from 621 under the reign of Emperor Gaozu and remained in production for most of the Tang dynasty until 907.