(I saw this movie (subtitled) many years ago during a samurai film festival, so please excuse any tricks played by fond memory. I've tried to avoid spoilers, too, but caveat that as well.)
I remember a great action picture, which reminded me especially of the old classic action westerns of the 1940's.
The movie opens with the escape of a young samurai after the local daimyo's lands have fallen to treachery. He soon joins a caravan of salt porters, who are secretly smuggling firearms back into the province in anticipation of the daimyo's return. The guns are crucial--they will give the daimyo the edge he needs to retake his lands.
Every possible samurai movie cliché is here. From the beautiful daughter of the caravan owner (who can steal a scene by standing in the background and sheathing her sword!), to ninja, pirates, secret traitors, the samurai's comic sidekick, daring rescues, mysterious smoke signals, rousing cavalry charges, and plot elements it would be unfair to reveal, capped by a one-on-one samurai showdown. This movie literally has it all.
It isn't deep, but it is great fun. I very much want to see it again. I don't usually buy movie DVDs, but the day I learn this one is available, it's mine (a status it shares with the 1960 animation Magic Boy). I could see it on a shelf with Yojimbo, The Santa Fe Trail, The Fighting Kentuckian, Dodge City, Rio Grande, and My Darling Clementine.