is a Japanese professor of comparative linguistics, specializing in Latin and Greek, and emeritus professor at Tokyo University. He studied comparative grammar under Kōzu Harushige at the department of linguistics at Tokyo University, and graduated in 1952. He studied abroad under a scholarship grant at Vienna University and returned to become assistant, and then full, professor at his alma mater. He was awarded his doctorate in September 1978 on the subject of kinship terminology in Indo-European languages. On his retirement, he subsequently taught at Hosei University. He is one of Japan's leading scholars in Indo-European studies, with a particular interest in etymology.