Bushidō (武士道, "warrior way") is a collective term for codes of ethics, honor, and ideal that dictated the samurai way of life in feudal Japan. It can be loosely compared to the western idea of chivalry.
The concept of bushidō dates back to early 17th century and is based on Shintoism, Zen Buddhism, and Confucianism. However, the modern idea of bushidō as being a strict code that was always adhered to, as well as many of the best-known tenets, were shaped in the late 19th century.
Though historically there was no unified code, as these varied from clan to clan, what has come to be known as the bushidō code is typified by eight virtues or tenets:
- Rectitude or Justice
- Courage
- Benevolence or Mercy
- Politeness/Respect
- Honesty and Sincerity
- Honor
- Duty/Loyalty
- Character and Self-Control
Despite being ninja, which are associated with their own loose idea of morality, the Ninja Turtles and Splinter often adhere to bushidō.
In The Way of Invisibility, Casey Jones informs the Ninja Turtles of graffiti that has been showing up all over the city which shows four turtles skewered on a sword. He thinks they should do something about it, but when they say it just sounds like a set-up, Casey says, "But this is a matter of honor! What about all that bushidoodoo stuff you guys always talk about?" to this Leonardo responds, "That's Bushidō, which has nothing to do payback for a bunch of nasty wall doodles."
In Turtles of Grayskull issue 1, Leonardo explains to Splinter that they are remaining on Eternia because Bushidō requires them to deal with Krang and Shredder as they are their enemies.