Taking into consideration what was known of the 'Kofun period' as a view point into the establishment of the Japanese Nation, historians and other experts came to this conclusion; that ancient Japan was formed during the early and middle portions of the 'Kofun period,' then to be fully developed and established during the late and final periods of the 'Kofun.'
日本国家の成立から考察すれば、前期・中期の古代国家の形成期を経て、後期から終末期にかけて日本の古代国家が成立したと考えられている。