Vietnamese Coin
Thien Quang Nguyen Bao

23.1 mm, 2.1 g
Obverse: Vietnamese Thien Quang Nguyen Bao

Tien Qing Yuan Bao

Reverse: plain
       Alan Barker:
The character on the right would appear to be Quang, or Ching in Chinese. Tien Ching Yuan Pao was a reign title used in the Liao dynasty (1111-1120) and again in the Western Hsia dynasty (1194-1204).
The Vietnamese copied many of the Chinese reign titles for 'un-official coinage'.

Chinese Coinage Web Site