Botanist. A graduate of the Faculty of Science of the Imperial University of Tokyo. In 1910 he became a professor of the 8th Higher School (later Nagoya University) and proceeded to work at the Education Institute of the South Manchuria Railway Company. During his tenure, he conducted research on lotuses in different places and attended Johns Hopkins University in the U.S. He successfully germinated ancient lotus seeds collected from Pulandian peat during his stay in Northeast China. Upon his return to Japan in 1931, he became a professor at Tokyo Woman's Christian University and Kanto Gakuin University. Postwar, he made every effort to revive the Shinobazu no Ike pond in Ueno, Tokyo. In 1951 he found ancient lotus seeds from 2000 years ago in the Kemigawa ruin in Hanamigawa district, Chiba, and successfully germinated and bloomed them. These lotus are named after him, as Oga lotus. His works include Hasu wo Kataru (Discussing About Lotus) and Hasu to Tomoni 60 nen (Together with Lotus for 60 Years).