[1][4] At the age of 5 years, he began training in the martial art of jujutsu under his great-uncle, Chojiro Ebashi (a samurai).

[6][7]: 68, 174 [8] In 1911, while studying business administration at Waseda University in Tokyo, Ōtsuka trained in various jujutsu schools in the area.

[1] On June 1, 1921 , Ōtsuka received the menkyo kaiden (certificate of mastery and licence to teach) in Shindō Yōshin-ryū jujutsu from Tatsusaburo Nakayama.

Jujutsu was not to become his primary art, however; in 1922, Ōtsuka began training in Shotokan karate under Gichin Funakoshi, who was a new arrival in Japan.

[12] In 1964, three of Ōtsuka's students Tatsuo Suzuki, Toru Arakawa, and Hajime Takashima) from Nihon University toured Europe and the United States of America, demonstrating Wadō-ryū karate.

[13] On April 29, 1966, Emperor Hirohito awarded Ōtsuka the Order of the Rising Sun, Fifth Class for his contributions to karate.

[1] In 1983, his son, Jiro Ohtsuka, became the second Grand Master of Wadō-ryū karate and honoured his father by taking the name "Hironori Ōtsuka II."