Yokohama Meibutsu: Otoko Katayama-gumi!

Fuente: AniList

When a number of biker gangs ranging from small to large started to appear in Yokohama, Hiromi Katayama united them at the risk of his own life. Set in the present, this OAV tells the story of Toshi Ikeda, a young rookie who returns to Yokohama to join Katayama's group. There, he will encounter an old friend and things will turn violent when the yakuza gang Mad Emperor attacks them.