Akira Kurosawa sued Sergio Leone claiming that Leone ripped off Yojimbo and based his Per Un Pugno De Dollari on it. Leone claimed that it was a common story used many times before notedly by Dashiel Hammet in his novel Red Harvest. A story about a gangster who infiltrates a gang and plays one side against the other.

Samuel Fuller, Maverick
That is exactly what happens in Sam Fuller’s excellent Underworld U.S.A. Cliff Robertson grows up on the wrong side of the tracks, as a youngster he witnesses his father’s demise at the bloody hands of a group of thugs in a back alley. The young protagonist swears to take vengeance on the men who offed his old man and when he grows up he starts tracking down the killers. They have moved up in the world becoming big time gangsters and Cliff uses everyone to set them up, the police, the gangsters themselves, even the woman he loves. This movie pulls no punches, a hit man runs down a 10 year old girl after befriending her and giving her some gum.

Richard Rust, Psycho Killer with Cliff Robertson
It seems her bookkeeper father has disappeared with some sensitive information about “Mr. Big”. Robert Emhardt the large guy with the snide attitude is great as the Big Boss, after Cliff (Tolly) sets up one goon, Richard Rust the happy hitman douses the poor slob with gas and lights him up. Emhardt is watching from the back seat of his his ’60 Caddy , he leans forward with a cigarette, “Gimme a light.” he orders.

Last One In Is A Rotten Egg!
This film is great, it really demonstrates how to make a lot out of a little, something Fuller was a master of. It inspired many filmmakers and is chock full of great ideas executed with style and power. Check it out.