The years of Kōgyoku's reign are not more specifically identified by more than one era name or nengō which was an innovation of Kōtoku's brief reign.Titsingh, pp. 43–54.
The years of Kōgyoku's reign are not more specifically identified by more than one era name or nengō which was an innovation of Kōtoku's brief reign.Tit.singh, pp. 43–54