This is an introductory book that introduces the spirit of Zen in an easy-to-understand manner, such as "What is Zen?" and "How is Zen useful?" and "What is the effect of zazen?" featuring junior high school students as the main characters.

In the first part, the main character, Ryota, enters junior high school and joins the kendo club, kendo is a traditional form of Japanese fencing using bamboo swords, but faces the fact that he cannot win a match. Then a kendo master enters the scene and teaches him the importance of the heart of Zen, and he overcomes his difficulties.

In the second part, Ryota shows how Zen wisdom helps him as he encounters various social issues in his working life.