This one is issued by Emperor Shih Tsung (Ta Ting, AD 1161-1189) of Chin Dynasty (Jing Dynasty, the Nu-Cheng Tartars). The inscriptions on the obverse are Ta Ting T’ung Bao (also in modern Chinese Da Ding Tong Bao). The reverse is blank. Its size is 25mmx1mm, about 4g. Da Ding Tong Bao is very popular in China. People all agree that it’s among the most beautiful Chinese ancient coins. It’s not rare and you can find one under $30 in very good condition. Lucky!
Very nice coin, so unusual with a blank reverse in that period. I think in the US they usually just refer to them as Tartars or Jing. Its a tougher empire to acquire.