About Mienoumi Tsuyoshi
Mienoumi Tsuyoshi (Japanese: 三重ノ海 剛司, Hepburn: Mienoumi Tsuyoshi; born February 4, 1948 as Gorō Ishiyama (石山五郎, Ishiyama Gorō)) is a Japanese former professional sumo wrestler from Matsusaka, Mie. He was the 57th yokozuna of the sport. After retiring he founded the Musashigawa stable and was a chairman of the Japan Sumo Association. He was the first rikishi in history who was demoted from the rank of Ozeki but still managed the promotion to Yokozuna. At first fighting under his real name, he took on the shikona of Mienoumi in July 1966, but did not adopt the Tsuyoshi given name until September 1976.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.