Bushido is a moral concept that warriors needed to learn as being Samurai. It is not a law or rule written on papers but a way of thinking or behaving practically obtained. Here is the source of Bushido (based on Bushido: The Soul of Japan by Inazo Nitobe).
The source of Bushido
Bushido is composed of Buddhism, Shintoism, and Confucianism. Buddhism teaches Samurai to keep themselves calm and accept their fate even they are confronted by death. This calmness can be acquired through meditation, Zen (here is more detail about Zen and Japan). Shintoism give a lesson of loyalty to the sovereign, respect to their ancestor, and the importance of filial piety. Confucianism which influenced Bushido requires to maintain “the 5 ethical relations among master and servant (the governing and the ruled), father and son, husband and wife, older and younger brother, and between buddy and buddy…”(Nitobe, Inazō . Bushido: The Soul of Japan, p. 10).
Regarding Confucianism, the 7 codes, 義(Gi/Justice), 勇(Yu/Courage), 仁(Jin/Benevolence), 礼(Rei/Politeness), 誠(Makoto/Truthfulness), 名誉(Meiyo/Honor), 忠義(chugi/The Duty of Loyalty) are fundamental but, at the same time, they are necessary in Bushido. 義 and 勇 are the basic requirements for being Samurai. 仁,礼, and 誠 tells them how to deal with others. 名誉 and 忠義 are the things that Samurai fought for in a battle.
義(Gi/Justice): what you must follow/keep as a person. It cannot be defined what it is, however, one said that 義 is the ability to make a decision on what you should do based on morality. The word, 義理(Giri) is often used as its meaning, it is the right reason/motivation for you to do. In other words, It is a sort of duty that you are obligated to do in order to keep the 5 ethical relations.
勇(Yu/Courage): taking a right action caused by a calm mental state.
仁(Jin/Benevolence): love, pity, or empathy to others. Samurai were required to be mannish and fair in the first place, however, benevolence was also necessary. “Bushi no nasake”, the tenderness of a warrior, means that Samurai show mercy but the mercy comes from fairness rather than emotion.
礼(Rei/Politeness): manifesting your empathy to others. To reach higher virtue in politeness, you should not brag your glory, not have a hatred for others, not seek your own interests, not offend people around you, not get upset, but should care about others, be generous, and benevolent. The utmost form of politeness is almost love.
誠(Makoto/Truthfulness): being faithful to yourself. Lying or unfairness is regarded as a coward. As utterances from Samurai’s mouth should be a fact, Samurai must take responsibility for what they said. However, 誠 is not so simple, you sometimes need to lie in order not to lose 礼.
名誉(Meiyo/Honor): Samurai’s dignity. This honor was nourished through experiences such as being said like “Don’t let others laugh at you!”, “Are you no longer ashamed?” and so on. Feeling shame sounds not good, however, it is important in order for Samurai to obtain their dignity. Nevertheless, keeping a good balance between other codes is also important.
忠義(chugi/The Duty of Loyalty): being loyal to your owner, even if you sacrifice yourself. The Samurai society was built based on the hierarchy between seniors and younger, and therefore 忠義 played an important role in the society. Samurai prioritized the public rather than the individual. They regarded themselves as an element of their society, to maintain its power or win over enemies, they were willing to die.
This is the Bushido. Samurai’s virtues are deep. It might be interesting to compare with Western philosophy. If you would like to know deeper about it, you should check this book out!
