Firstly, following detailed research that appeared in Yoshihiko AMINO's "Wakasa no kuni ni okeru shoensei no keisei" (The formation of the manor system in Wakasa Province) (1969), Susumu ISHII's "Insei jidai" (The Age of Cloistered Emperors) (1970) and "Oota Fumi" (The letters of Oota) in "Sobu no bushidan" (Bushi groups of the Sobu region), which appears in "Kamakura bushi no jitsuzo" (The Real Face of Kamakura Warriors) (1978), it became clear that most manors were established after the mid-12th century, during the reigns of the Cloistered Emperors Toba and Gotoba, and that by the time this large-scale expansion stopped in the 13th century, the ratio of shoen to national land was on average of six to four, or about even.
そのひとつは、網野善彦の1969年「若狭国における荘園制の形成」や石井進(歴史学者)の1970年「院政時代」、1978年の「相武の武士団」（『鎌倉武士の実像』に収録）における「太田文」の詳細な研究から、荘園がもっとも盛んに立荘された時期は、12世紀中葉以降の鳥羽天皇・後白河天皇院政期であり、更にその大規模荘園の乱立が完了した13世紀においてさえも、荘園領と国衙領は地方により相違はあるものの、平均すれば6対4とほぼ半々であることが明らかになった。