However, his idea invited pointed objections and Yoshimi TODA and his group proposed the theory that the system was established after the period of the government ruled by the retired Emperor, and Keiji NAGAHARA and his group proposed another theory that the system was established in the Northern and Southern Dynasties period (in Japan), the civil war period.
しかし、激しい反論を生み、院政期以降を成立期とする説（戸田芳実など）、南北朝時代(日本)内乱期を成立期とする説（永原慶二など）が提起された。