Feudalism is all about a fair exchange between all rankings in Japan that lasted 700 years because people felt secure. Feudalism in Japan had a shogun then daimyos, after them came samurai and the peasant/farmers came last. All rankings gave each other protection and a place to live while peasant/farmers gave the upper class food and did chores. Feudalism gave structure in society because everyone knew their spot in society. Without feudalism there wouldn't be any structure and people wouldn't have a custom that lasted up to the late 18 hundreds , which clearly was good since it lasted long.
Bushido is the code of the samurai that took form in 17th century "the way of the warrior". Samurai were expected to be honest,fair,fearless of death, loyalty, and value personal honor. The one important duty that the samurai had was to be loyal towards his lord so if anything were to happen to the lord, he would die for him or avenge him if he were murdered. Seppuku was the way a samurai would die to keep his personal honor rather then die in battle from an enemy. Bushido kept structure in society between the samurai and also others, because they were loyal people who would defend themselves and others in times of need. Without Bushido samurai would probably be dishonest and wouldn't have been part of history and the feudal system.
Aritocracy during the Heian period had a type of government that was controlled by what rank you were in. Depending on what family you were born into your personal qualities /skills mattered more than if you were in a higher rank.There were 9 ranks all together, the first three were the highest ranks while the others were considered low rankings. All ranks received profits of rice and money from taxes that peasants paid for. The 6-9 rankings were filled by clerks, law ,medicine, and minor officials. The high rankings held a fan of 25 folds, 4-5 held a fan worth of 23 folds, and the lowest class had a fan of 12 folds. This helped society structure itself because once again everyone knew their place in society and how they had to contribute in ways they could. Without Aritocracy people wouldn't have a place in the rankings,even though it wasn't fair towards the people at the bottom.