Ushitora's gang includes giant henchman Kannuki (Tsunagorû Rashômon), and Ushitora's two brothers, obese bully Inokichi (Daisuke Katô) and smug pistol-toting Unosuke (Tatsuya Nakadai).
Frequent Kurosawa co-star Takashi Shimura shows up as sake brewer Tokuemon, installed by Ushitora as town mayor. Tokuemon is infatuated with slave woman Nui (Yôko Tsukasa), whom he has seized from her husband and child.
How others will see it. By 1961, Kurosawa was regarded as the greatest Japanese director in the West, even greater than the less interesting Yasujirô Ozu. The film picked up two wins at the eurocentric Venice Film Festival, and a minor Oscar nomination (Best Black and White Costume Design), but the acclaim was a bit less than was the case for a prior Kurosawa effort, The Seven Samurai.
But the influence of Yojimbo is perhaps greater. The film was blatantly copied in A Fistful of Dollars by Sergio Leone, the first significant film in his career (and also his leading man, Clint Eastwood). Later, it was remade again as Last Man Standing, and (to a lesser extent) Miller's Crossing.
Today, Yojimbo is revered. At imdb, it has a lofty 8.2 user rating, and a high vote total (125K) for an old black and white film. The user reviews lavish praise on Mifune even more than Kurosawa. The consensus is that it is even more entertaining than the typical Kurosawa-Mifune collaboration, albeit perhaps not as "deep" as some of their other projects.
How I felt about it. Yojimbo is very good Kurosawa, but it is not great Kurosawa. It might not be among his ten best films. It sets up the myth of the good-guy martial arts superman, which at least Kurosawa does better than would later be the case with Zatoichi The Blind Swordsman, Bruce Lee, Billy Jack, Chuck Norris, etc. This probably has to do with Kurosawa's underestimated talents as a screenwriter.
I have some problems with the story. Tokuemon is obsessed with Nui, and puts great stock in her return, but why would Ushitora care? He can always install someone else as the puppet mayor, as he did Tokuemon.
Thus, there is an insufficent motive for Ushitora to keep Sanjuro alive once he has been proven a traitor, or for Ushitora to agree to a prisoner exchange of Seibei's milquetoast son Yoichiro for Nui, or for Ushitora to delay wiping out Seibei's gang.
Of course Kannuki and Inokichi would open the enormous chest in Sanjuro's cell to see if he is hiding there.
In the film's climax, Sanjuro confronts Ushitora's entire gang. The logical outcome is that Unosuke will shoot Sanjuro, killing him before he can get close enough to slice anyone up.
Sanjuro's stated motive, to eliminate both gangs and their leaders to save the town, has a flaw. Once they are gone, there is no one left in the village alive except for the silk merchant (a murderer), the coffin maker (a war profiteer), the tavern owner, and a few prostitutes who will soon leave town.