The first custom Bushido is the samurai code of honesty, loyalty, and honor. Bushido helped structure in Japan because Samurai were not dishonest or rude. The society would be different without due to samurai being so disrespectful.
The seven rules of Bushido.
The second custom I chose is Government: Rule of Shogun which made Samurai the warrior class. The Rule of Shogun had kept structure by protecting Japan for many years. Society would have been different because they may have lost some wars without the samurai.
A samurai in battle.
The third custom I chose was Buddhism is the culture the Japanese chose, there were two types of Buddhism Zen and Amida Buddhism. The religion of Buddhism keeps structure because it kept the Japanese from disrespecting other people or other religions. It would be different without Buddhism because Zen Buddhism makes sure you use common sense.
These are 3 of many customs that the Japanese had used or been through.