While Yojimbo is a kick-ass Western, it also deals with the conflicts of a society that is being heavily influenced by outside forces, specifically that of the United States.
An opening card in the movie tells us that the year is 1860 and the Tokugawa regime has come to an end. This was the time period that the American Commodore Perry came to Japan and forced them to begin trading with the West. Everything points to the people and the town in Yojimbo as being tainted by capitalism and Western influences.
Traditionally, Japanese villages were agriculturally based, but the main products of the Yojimbo town are silk and sake, two items that need to be manufactured in some form. In the beginning as Sanjuro is traveling, he comes across a son telling his father that he wants to go to the city in order to make money instead of staying home and running the farm. Later on, Sanjuro spares the life of the boy and tells him to return to his family. Even the two rival gangs can be looked at as business conglomerates. Although they are composed of family members, they recruit outside mercenaries for help and are willing to destroy the idea of traditional family. This is especially apparent in the hostage exchange scene where a son is returned and his mother hits him and vilifies him for his cowardice and the poor position his capture had put their side in. The idea of warring clans, which would otherwise have great validity in traditional ideals, is undercut here because of the strictly economic basis of the struggle. This biggest Western taint of them all appears when it is revealed that Unosuke has managed to get a handgun, the modern replacement for the traditional sword.
The man that ends all of this and cleans up the town is a samurai, a link to Japan’s past whose power is already fading. In the end, he declares, “Now this town can have some peace and quiet” and walks off, however we the viewer know that the West will continue to creep in.