The mass of a Tensho oban was to be the same as a Kin (plate of gold), equivalent to kyome (unit of weight of Kin) ten ryo (a unit of weight), as well as forty-four monme (a monetary unit), however, counting loss during the process of finishing, re-dyeing and wear during circulation, it was regularly minted of the equivalent gold to forty-four monme two bu (forty-four monme is about 165g, forty-four monme two bu is about 173.25g).
質量は金一枚すなわち京目拾両（四十四匁）を基準としているが、実際には色揚げによる減量および磨耗などを考慮し二分の入り目が加えられ、四十四匁二分が規定量目である。