Samurai II: Duel at Ichijoji Temple (1955)

The middle chapter is where Mifune's Musashi learns to hold still, and watching that wild body acquire discipline is the trilogy's real pleasure. The fights grow sharper too: an early bout against a chain-and-sickle fighter shows how inventive Inagaki gets with weapons and space. It also brings in Koji Tsuruta as the elegant Kojiro Sasaki, the rival whose cool polish makes Mifune's rough edges look even rougher. Watch it straight after the first film, since it assumes you know Musashi's journey so far.