There were three important customs in Ancient Japan. One of them was the Feudal System. This was used to help organize their society. Everybody had their own job to do to help their society be successful and thrive well. This helped structure their society by helping organize their society because it organized what everybody did, and what everybody had to do everyday. This made their society way more easier instead of having everybody all over the place doing nothing. Their society would be way different without it because, there would be no protection for their citizens, and they would be attacked. If they didn´t have a organized society, they would be all over the place and have no idea what to do.
The second custom was Samurai. A samurai is a warrior taught to protect a certain area or person, a samurai is also a member of a powerful warrior warrior class in Japan. They would be protecting peasants and the Shogun from attackers. They would also fight in wars to protect/defend Japan. Samurais helped structure Japan´ society by them having a type of security like how we do nowadays to make us feel safe. They would defend the innocent and weak, and defend attackers trying to take over Japan. Society would be way different without it because if they didn't have a form of defense, Japan would be attacked, and they wouldn't be able to save their society, just how it is nowadays, without defense, we would be attacked.
Craftsmen were builders, very skilled with tools and measurements. They built homes, buildings, weapons for the samurai's and such. This custom helped structure society by craftsman building homes , to be warm and and helped them from bad weather, and they could keep their belongings safe. Without craftsman, there wouldn't be any weapons for the samurai's to helped defend citizens and Japan. There wouldn't be any safe place for the people to rest, and be warm from severe weather. Craftsman were a huge part of everything we have in the world right now.