When he was forty, he reached an established theory through the words of Cho Sai (Zhang Zai), 'the mind unites nature and emotion,' and 'seisokuri' (xing ji li) (human nature is natural law) of Tei I (Cheng Yi), and established Bin-gaku (Bin neo-confucianism).
40歳の時、張載の言葉という「心は性と情とを統べる」と程頤の「性即理」による定論を得、一家を成してびん学（びんがく）を起こした。