Satoyama Kōsaku is a retired professional sumo wrestler from Ōshima, Kagoshima Prefecture, Japan. A former amateur sumo champion at Nihon University, he entered professional sumo in 2004 and first reached the top makuuchi division in 2007. His highest rank was maegashira 12. He spent much of his career in the jūryō and makushita divisions, and won a yusho or tournament championship in each. He won promotion back to the top division in 2014 after a seven-year and 37-tournament absence, the longest ever. He was a member of Onoe stable. He retired in November 2018 and is an elder of the Japan Sumo Association under the name of Chiganoura.

Nihon University , abbreviated as Nichidai (日大), is a private research university in Japan. Its predecessor, Nihon Law School, was founded by Yamada Akiyoshi, the Minister of Justice, in 1889. It is one of Japan's leading private universities. The university's name is derived from the Japanese word "Nihon" meaning Japan. Nihon University now has "16 colleges and 87 departments, 20 postgraduate schools, 1 junior college which is composed of 5 departments, 1 correspondence division, 32 research institutes and 3 hospitals." The number of students exceeds 70,000 and is the largest in Japan.