Satoyama Kōsaku (born May 31, 1981) 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.