He was born the second son to Harukazu MITSUBUCHI, a member of the Shogun's personal army in the Ashikaga Shogunate administrative system, and to Chikeiin, the daughter of Nobukata KIYOHARA, a famous scholar of Confucianism and Kokugaku (national learning).
足利将軍家の奉公衆三淵晴員の次男で、母は著名な儒学・国学者清原宣賢の娘・智慶院。