The gambler's counterattack (1971)

Aiba is a gang boss who has just got out of jail, and finds everything has changed. His old gang has broken up, and only a few people still respect him. So he becomes a consultant to another gang who are about to be clobbered by a much larger gang moving in from out of town. Aiba proves a crafty tactician, and does very well at playing gangs off against each other in order to save the smaller gang. His advice is not always taken by those he tries to help, but he is generally proved right.