He was also known as  in his youth. At age five, the young Tatsumi went to Kuwana with his adoptive father, and at age 8 entered the domain school, Rikkyokan, studying literature and martial arts, and receiving a commendation for academic excellence at age 15.
Tatsumi was born in Edo as the third son of a retainer of Kuwana Domain name Machida Dendaiyu. He was later adopted by his uncle, a fellow retainer named Tatsumi Sakujuro Takashi, whose surname he took.