Taiho Koki (????; born Koki Naya, Ukrainian: ???´? ????´???, Ivan Boryshko; May 29, 1940 – January 19, 2013) was the 48th yokozuna in the Japanese sport of sumo wrestling.
He became a yokozuna in 1961 at the age of 21, the youngest ever at the time.
He won 32 tournament championships between 1960 and 1971, a record that was unequalled until 2014.
His dominance was such that he won six tournaments in a row on two separate occasions.
He is the only wrestler to win at least one championship every year of his top division career, and he won 45 consecutive matches between 1968 and 1969, which at the time the best winning streak since Futabayama in the 1930s.
He was a popular grand champion, especially amongst women and children.
After retiring from active competition he became a sumo coach, although health problems meant he had limited success.
When he died in January 2013 he was widely cited as the greatest sumo wrestler of the post-war period.
Since then Hakuho, who regarded Taiho as a mentor, surpassed his record by winning his 33rd championship in January 2015.