He oversaw the development of the system from his home in Shizuoka, Japan, where his dojo, the Yoseikan, was often visited by martial arts practitioners from all over the world.

Under the tutelage of Jigoro Kano, the founder of judo, as well as the renowned Sanpo Toku, Mochizuki became the youngest member of the Kobudo Kenkyukai – an organization for the study, preservation and development of classical martial arts – established within the Kodokan.

His idea of combating communism with the application of the principles of "mutual welfare and prosperity" and of "the best use of energy" of Jigoro Kano contributed to the development of his region.

[5] He was the 3rd Aikido Division head of the Kokusai Budoin-International Martial Arts Federation (IMAF Japan) after Ueshiba and Tomiki.

He taught at the dojo of Shizuoka until nearly the end of the last millennium and spent the last years of his life in France with his son Hiroo.