Manga works and manga culture of any time cannot be discussed out of the context of history and reality. The same applies to the phenomenal Japanese shōnen manga when we look at its development for the past 70-some years. Emerged right after the war, shōnen manga bore the duty of anti-war education and at same time served as a motivation that stimulated the youth to overcome the national predicament. In exploring “what makes shōnen a shōnen”, shōnen manga found its way out of the everlasting “fighting” circle, switched from the battle of muscle to the competition of intelligence. As a mature genre, it reflects the development of Japanese society and “postwar culture”.