@The first story for boys written by Satô Kôroku, at the age of 52, who was already famous as a novelist and dramatist. Katô Ken'ichi, the editor of the magazine Shônen Kurabu [Boys' Club], asked him to contribute to it. At first Satô was furious at having been asked to write stories for children, but finally was persuaded by Katô. Because of his story the magazine increased its number of issues tremendously. It was published in book form and 10,000 copies were printed.
@The title of the story is taken from a famous dormitory song of Daiichi High School. Four boys who have problems to be solved are characters in the story. How they overcome difficulties is described in Sato's articulate, classical Chinese-like style. Sakai Iwao is a son of a deputy mayor, who protests against his father's corruption. The story suggests that a sense of justice should sometimes surpass filial piety. Yanagi Kôichi is a son of a trader in sundries. He makes friends with Aoki Senzô, a son of a tofu maker, although they belong to different classes. Senzô does not give in to his circumstances but lives sincerely and patiently doing his best to improve his lot in life. Tezuka is brought up in good surroundings but he is so dependent that he yields to temptation and corruption. Sato's idealism, which links justice and friendship to social success, is the strength and the weakness of the book. The method of describing the boys' penitence and growth through their conflicts became a model for postwar children's literature.
@The book was reprinted many times. It was made into a movie in 1929 and 1935. A reprint of the original was published by Kôdan-Sha in 1970. Text and illustration of the first edition was included in the complete works published by Nihon Tosho Center in 2000.