Not quite a samurai movie, but Sancho The Bailiff is a period piece about slavery in feudal Japan that is both gorgeous and heartbreaking. I don't think I'd watch it a second time because it's so painful but what a great film!
Most of these films can be found on the good ol' Internet Archive. In fact if you have Kodi you can stream them directly. Just install the Kore remote on your Android device and share a link with Kodi. But don't forget to drop our friends at archive.org a donation to say thanks for all their efforts.