Japanese freestyle featherweight wrestler who was the undefeated world champion in 1962 and 1963 and an Olympic gold medalist in 1964. He competed in more than 300 matches and never lost a bout in his career.

Watanabe won his first national championship at the age of 19 and defended this title four times (1960–64) while attending Chuo University in Tokyo. He startled observers in June 1962 by easily winning both the United States amateur title in New York City and the world championship in Toledo, Ohio. He retired after his 1964 Olympic victory in Tokyo to work for an advertising agency. Most of Watanabe's 186 victories for Japan were won by fall (i.e., briefly pinning an opponent's shoulders to the mat), and none of his opponents in these matches scored a single point against him.