Brothers'Code - The Back Relation (1968)

Original title: 兄弟仁義 逆縁の盃

Yakuza Kojima appeared in Yokkaichi in search of her mother who died when she was young. There he met Torajiro, a master of kendo, who had just left prison after slashing his adoptive father who stole his son's wife. Torajiro was on his way to his brother-in-law, Iwai. While talking about themselves, they someday felt something similar to friendship.