日外アソシエーツWhoplus 「大横田 勉（オオヨコタ ツトム，水泳選手）」の項 was a Japanese freestyle swimmer. While a student at Meiji University, he set national records over 200 m (2:14.6) and 400 m (4:50.4). He was selected for the 1932 Olympics and won a bronze medal in the 400 m event, despite suffering a severe bout of gastroenteritis before the Games.
References Tsutomu Oyokota. sports-reference.com
Further reading
Lohn, John. Historical Dictionary of Competitive Swimming. Scarecrow Press, (2010).