In view of the existence of the official history book which described only one emperor, such as "Shoku Nihonkoki" and "Nihon Montoku Tenno Jitsuroku" (fifth of the six classical Japanese history texts), or the one whose compilation work lasted long and eventually stopped without being completed, such as "Shin-kokushi," some people assert that the organization was established intermittently during the period from the late 9th century to the early 10th century.
『続日本後紀』や『日本文徳天皇実録』のように1代の天皇のみを扱った国史が編纂されたり、『新国史』のように長期化して最終的に完成しなかった例もあり、9世紀後半から10世紀前半には事務機関が断続的に設置されていた時期があったとする説もある。