Seismologist. He graduated from the Department of Physics of the Imperial University of Tokyo in 1894, and concurrently served as both a professor of the Military Academy and an assistant professor at the Imperial University. He was active as a committee member of the earthquake prevention survey committee, and in 1905 he had a major argument with OMORI Fusakichi in relation to the prediction of the Great Kanto Earthquake. At the time of the Great Kanto Earthquake of 1923, he played a central role in research activities as the secretary of the Earthquake Prevention Investigation Society. He established the Seismological Society in 1929 and assumed the position of president. He contributed greatly to the establishment of the basic methods for current earthquake prediction research. Member of the Imperial Academy.