Miyamoto Musashi (1954), directed by Yasuo Kohata.
There is a particular story involving Musashi in a practice duel with another swordsman. At the end of the duel the other man calls it a draw whereas Musashi proclaims he would have killed the other man. The man insists on a duel to the death, and Musashi quickly kills the man. This episode appears as a setpiece (involving other characters) in the movie Seven Samurai directed by Akira Kurosawa, and (in suitably modified form) in the American Western remake of that film, The Magnificent Seven.