New Battles Without Honor and Humanity 1
新仁義なき戦い / New Battles Without Honor and Humanity 1 (1974)
Bunta Sugawara is Miyoshi, a low-level assassin of the Yamamori gang who is sent to jail after a bungled hit. While in stir, family member Aoki attempts to seize power from the boss, and Miyoshi finds himself stuck between the two factions with no honorable way out.