Due to the different historical developments and political traditions of China and Japan, Chinese concepts of legitimacy could not be applied to Japan without major modifications. Tokugawa historians demonstrated a high level of flexibility and creativity in their discussion of political legitimacy. Some Chinese concepts were reinterpreted to fit into the Tokugawa system. For instance, the mandate of heaven was used primarily to discuss the right to govern and denied a Chinese-style "revolution" and dynastic change. Using major Tokugawa historical writings as the main references and highlighting the legitimacy of the Southern or Northern Courts as well as the legitimacy of the Edo bakufu, this study examines the making of Japanized concepts of legitimacy in Tokugawa historiography. It sheds light on understanding how Tokugawa historians creatively modified and appropriated Chinese historical ideas and terms to accommodate Japanese tradition and the Tokugawa political system.