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. The Kaiyuan Tongbao was notably the first cash coin to use the inscription tōng bǎo (通寶) and an era title as opposed to have an inscription based on the weight of the coin as was the case with Ban Liang, Wu Zhu and many other earlier types of Chinese cash coins. The Kaiyuan Tongbao's calligraphy and inscription inspired subsequent Central Asian, Japanese, Korean, Ryūkyūan