He won a gold medal in the heavyweight division (above 80 kg) at the 1964 Summer Olympics in Tokyo and a world title in 1965.

He placed second in the All-Japan Championships in 1960 and 1961, both times losing to the future Olympic silver medalist and lifelong friend Akio Kaminaga.

He managed to avoid the armlocks and threw Kiknadze at the five minute to advance to the final against Rogers, who was about 30 kg heavier.

[4] After graduating, Inokuma became a judo instructor for Juntendo University and the Tokyo Metropolitan Police Department.

Inokuma died by suicide by seppuku in 2001, possibly due to financial losses suffered by his company.