Samurai I: Musashi Miyamoto (1954)

The place to begin. Hiroshi Inagaki adapts Eiji Yoshikawa's novel about the young Takezo, the hothead who will become the swordsman Musashi Miyamoto, and Mifune plays him as pure feral energy: shouting, bolting through forests, all instinct and no discipline yet. That rawness is the point, because the next two films tame it. Shot in rich color at a time when most samurai films were black and white, it received an honorary Oscar for best foreign film, and it is the best way to see how a Mifune hero is built from the ground up.