It is thought that shichusen started to be produced and circulated just after Wado-kaichin silver coins were coined in 708, and an official ban against shichusen was issued in the following year of 709.
私鋳銭は、和同開珎が鋳造（708年）された直後から製造、流通していたと考えられ、翌年（709年）には早くも私鋳を禁ずる詔が出された。