Well, if this film doesn't put hair on your chest, nothing will.
Look up 'film noir' in the dictionary and there should be a picture of Robert Mitchum in The Yakuza, alongside Bogie in The Maltese Falcon. It's that good of a film.
The theme is about honor, or "giri." The last bastion of manhood in an relativistic world ambivalent towards heroism, unsure about any values, moral or otherwise, and gone to hell.
Against this background, you may be a tad on the shady side of the law, but do you keep faith with your friends?
For that matter, would you risk taking a bullet for someone you personally loathe but whom you "owe" because he's saved the life of your wife and child?
The plot begins when Mitchum is approached by an old army buddy that he hasn't heard from in decades, save for the annual obligatory Christmas card. His daughter's been kidnapped by Japanese mobsters and he needs his help.
As to Mitchum, his character is established in one line.
"You've been successful?"
Mitchum: "That depends on how you figure those things."
True enough. He has no family, no friends, no one even remotely close. The film noir loner, now in his sixties.
He goes back to Japan, links up with the only woman he ever loved, and the one enemy who can help him gain entry into the dark world of the Yakuza; an ultra-traditionalist latter-day Samurai ( Tanaka Ken ) who "owes" Mitchum.
One small problem, he's no longer a Yakuza. He's been out of the mob for years. When Mitchum finds out this unpleasant bit of inforation and blurts out "I can't ask you to do that!" Tanaka Ken quietly replies: "You already have."
The aged warriors go to it again. A great story of love and betrayal. Acted in a style of understated whispers between flashing katanas that bring the house down.