This was not included within the main part of the developed samurai theory, but a lightly stated sentence related to how the bushi families split into enemies and allies during the period of the Northern and Southern Courts (Japan) that left a great impact in later bushi and bushidan studies since that time.
この一文は、武士論を正面から展開する中でのものではなく、南北朝時代に武士の家が敵味方に分裂したことに関連してサラッと書かれた一文なのだが、しかしその後の武士・武士団研究に大きなインパクトを与えた。