It is said that in his later years, Ichiro became to believe in Christianity influenced by Aizan, quit drinking alcohol, and eventually died as a 'typical fatherly Tokugawa samurai' (from remembrance of Aizan).
晩年は愛山の影響を受けてキリスト教を信じるようになると、酒を断って「徳川武士の典型的老士」（愛山の回想より）として没したという。