After World War II, geochemistry in Japan began with research on hot springs. During the post-war occupation period, research in the field of atomic energy was prohibited and exchanges with foreign countries were restricted. Consequently, hot springs research was thought to be a unique area of research that could be conducted in Japan. Postwar geochemistry research in Western countries, particularly in the United States, focused on trace elements, radioactive isotopes, and stable isotopes. Such research required high-precision analysis equipment. Japanese researchers who lacked the necessary research environment were then able to travel abroad. They began to conduct research in the United States and bring the results back to Japan. Thus, geochemical studies in Japan progressed. The intellectual stimulation researchers experienced abroad was also significant. The history of geochemistry in Japan from 1945 to 1965 is described, covering ten topics: hot spring chemistry, radiometric dating, the works of Akimasa Masuda and rare earth chemistry, stable isotope geochemistry, cosmochemistry, the works of Paul Kazuo Kuroda and nuclear chemistry, Antarctic science, sociogeochemistry (social geochemistry), textbooks published in Japan, and societies and laboratories newly established during this period.
