If you loved Samurai I: Musashi Miyamoto, try Incident at Blood Pass
A bridge between a film you've already seen and one most people haven't. Incident at Blood Pass has roughly 8.0× fewer votes than Samurai I: Musashi Miyamoto — it's a deeper cut, not a mainstream recommendation. Here's what they share, and what the second one does that the first one doesn't.
What they share
Both films are directed by Hiroshi Inagaki, and they both carry the slow burn mood tag, and they sit in Action / Drama territory. If that's the register that drew you to Samurai I: Musashi Miyamoto, the second film will land in a comparable space — through a different lens.
What Incident at Blood Pass is
You assume you're a ronin waiting in a mountain pass when you reach an inn and get tangled in a gang robbing shogunate gold on the road. The job asks you to kill everyone inside, but then you uncover the heist is a setup and your loyalty fractures. Inagaki's steely gaze lingers on this moment of choice.

