This is a concept that has fascinated me for some time. What I know is that a very westernized Japanese man named Nitobe wrote a book comparing Bushido and samurai to chivalry and medieval knights.

What is the true history of Bushido? Did the Samurai class ever have a uniting set of ethics and codes that made them a distinct part of feudal society?

How did the Japanese turn this philosophical concept into a nationalistic idea that fueled propaganda, State Shinto, and imperialism?

Any historical/cultural input would be much appreciated!