Bloodstained Clan of Honor (1970)

It takes place in the sunset days of the yakuza in the 1970s. The postwar turmoil that created the black market and lubricated illegal business opportunities was giving way to Japan Inc. A young Bunta Sugawara takes over as the oyabun of a crime syndicate in Yokohama, where he is struggling to keep operations at the port there alive. As his syndicate is eroding quickly, a major heavy industries company offers his gang the chance to chase some vagrants out of a shantytown where they are squatting on land where a factory is to be built. The job would secure steady profits for Bunta's crime ring for years to come. However, Bunta and other members of his outfit grew up in the shanty, and they would be muscling their friends and neighbors. This sets the stage for an internal struggle that complicates the violent struggle with a rival mafia organization in Tokyo.