Aoiyama Kōsuke (碧山 亘右) (born June 19, 1986 as Daniel Ivanov, Bulgarian: Даниел Иванов, in Elhovo, Bulgaria) is a professional sumo wrestler or rikishi. He made his debut in 2009, reaching the top division two years later, debuting in the November 2011 tournament. He has won three Fighting Spirit awards and one kinboshi for defeating a yokozuna. His highest rank has been sekiwake. He is one of the heaviest competitors in sumo, weighing around 200 kg for most tournaments.