Bakudan

Bakudan is a manga by Akira Miyashita published in Weekly Shōnen Jump in 1995.

Plot
The story revolves around a fresh-out-of-juvy punk who aspires to become the greatest yakuza in Japan, but whose career takes a drastic turn with an encounter with a retired boxer, who entrusts him with his past dream of becoming the first Japanese heavyweight world champion boxer.