The historiography of geoscience in the 20th century in Japan is reconsidered through 57 volumes of diaries (1914-1963) of Mochizuki Katsumi (1905-1963), a geology professor at Shizuoka University, from the following four viewpoints: 1) Scientific thought of geotectonics: Considering Mochizuki's own theory of geotectonics from his relations with other researchers such as Otuka Yanosuke (1903-1950), professor at the Earthquake Research Institute and the Faculty of Science of the Imperial University of Tokyo; 2) Mutual relationship between geology and geography: Tracing Mochizuki's teachings and research in the two disciplines at the higher schools of Kanazawa and Shizuoka; 3) History of geoscience education: Illustrating the transition of ‘geoscience’ including human geography, from the World War II era to the post-war period; 4) The life history of a scientist: Positioning a personal history, which records details of educational reforms in the history of universities and cultural history of Japan.
