After the defeat of the war, Japan faced the challenge of not returning to the fascism before the war and overcoming American democracy at the same time. To overcome this situation, Ishimoda Sho published Discovery of the History and Nation. This study analyzed the book to reveal ① how Ishimoda used Stalin’s theory, ② why he introduced the limitations of positivist historical view and Tsuda Sokichi, and reconstructed its meaning to reveal how the connection between naturalness and the emperor was established. First, it covered Stalin’s theory and the perspective toward the world history. Ishimoda interpreted the world is divided into bourgeois nationalism and proletarian nationalism, not the West and the East. Ishimoda viewed that Japan formed bourgeois nationalism in this global trend. He argued that Japanese fascism was developed because it suppressed the nationalism of the oppressed people in such global trend. He attributed the cause to the “uncritical” following of “Western theory,” in other words, a lack of subjectivity. Ishimoda was critical of the idea that the nation existed from ancient times, but agreed to the fact that the emperor is manifested throughout the history is connected with the naturalness of Japan. This discussion posed the risk of eventually agreeing to the combination of Japan’s “naturalness” and the emperor as universality. Ishimoda combined anti-Americanism with nationalism of the Asian oppressed nation through this very global idea. This marked the starting point of Japan’s post-war nationalism, and its content was the emphasis of a transparent yet chaotic Japanese-ness. In other words, it returned the national nationalism of postwar Japan to colorlessness and introduced a hybrid nationalism that called a new mass nationalism, paving the way for a return to “natural imperialism” at any time.