It is said to have been written between the Kohei era (1058 - 1064) during the reign of the Emperor Goreizei and the Enkyu era (1069 - 1073) or Joho era (1074 - 1076) during the reigns of Emperor Gosanjo and Emperor Shirakawa.
成立時期は後冷泉天皇朝の康平頃とも、後三条天皇・白河天皇朝の延久・承保頃ともいう。