New Battles Without Honor and Humanity 2: Head of the Boss(1975)

Overview:

The seventh in the shocking "Jingi Naki Tatakai" movie series, which exposes the true lives of the yakuza that is hidden by a mask of "jingi". The next stage of this continuing drama is the Kanmon Channel where the Owada and the Kyoei groups are battling for territorial rights and drug smuggling. The Owada sends their man, Tetsu, and his friend Shuji to kill the Kyoei boss. With the promise of fame and riches, Shuji takes the fall and goes to jail for 7 years. But when he's released, he discovers that he and Tetsu have been all but forgotten by the Owada. Feeling betrayed, Shuji takes matters into his own hands and becomes an unsuspecting pawn in an internal conflict and an assassination attempt on the Owada boss. And now angered, Shuji seeks revenge...