The multifaceted role of Confucianism(s) in Japan constitutes a complex problem in the history of intellectual exchange, particularly regarding the reasons of its transmission from China and its impact on Japanese identity formation. The Tokugawa era (1603-1868), representing an excellent basis for the exploration of this manifold phenomenon, marks the compilation of the Dai Nihon shi (The History of Great Japan, 1657-1906), the monumental history writing project of the Mito school, an initially progressive organization which ultimately became associated with xenophobia. Taking this source and its celebrated initiator, Tokugawa Mitsukuni’s case as an example, the project examines the shifting characteristics of early modern Japanese history writing and the perceptions of otherness through the utilization of Confucian concepts and terminology. It also questions the pertinence of the term sakoku (seclusion) by reconsidering received assumptions about the controversial position of Mito through a unique combination of textual analysis and digital methods.