He was a representative scholar of eastern history, together with Kurakichi SHIRATORI, before the war; their dispute on Yamatai-Koku kingdom and periodization theory about Chinese history divided the academic society into two.
白鳥庫吉と共に戦前を代表する東洋史学者であり、邪馬台国論争、中国に於ける時代区分論争などで戦前の学会を二分した。