The cause of the Japanese feudal system was likely the rising of the Shogun (basically Japanese warlords) and large imperial Daimyo (basically like royal families). The feudal system was basically a single major social hierarchy which had the Japanese Emperor at the top (Though he was essentially more of a figurehead) and merchants at the bottom. During the feudal era, the merchant and artisans classes were considered far lower than the warrior class, feudal Japan valued strength and honor over sly salesmen and profiteers.