Tamanoumi Masahiro, Japanese sumo wrestler, the 51st Yokozuna (born 1944)

Tamanoumi Masahiro was a Japanese professional sumo wrestler from Aichi. He was the sport's 51st yokozuna. Making his professional debut in 1959, he reached the top makuuchi division in 1964. He won six tournament championships and was runner-up in 12 others. Earlier in his career he also earned six special prizes and four gold stars. He was promoted to yokozuna simultaneously with his friend and rival Kitanofuji in January 1970 and the two men represented the dawning of a new era after the dominance of Taihō. He died suddenly in October 1971 after a delayed appendectomy.

Makuuchi (幕内), or makunouchi (幕の内), is the top division of the six divisions of professional sumo. Its size is fixed at 42 wrestlers (rikishi), ordered into five ranks according to their ability as defined by their performance in previous tournaments.