Tomozuna stable
Kaiō won his first top division tournament championship in May 2000 from the "komusubi" rank, defeating "yokozuna" Takanohana and three "ōzeki" and losing just one bout to Akebono. It was the first top division "yūshō" by a wrestler from Tomozuna stable since Tachiyama in 1916. He attributed his victory partly to cutting down on his beer consumption. Set a target of eleven wins by the Japan Sumo Association for promotion to "ōzeki" in the following tournament in July 2000, he achieved the necessary total on the final day and his promotion was confirmed a few days later. He was 28 years of age, and the 44 tournaments it took him to reach "ōzeki" from his top division debut was the second slowest ever. Nevertheless, he went on to maintain the rank for eleven years, eventually becoming the oldest "ōzeki" since the start of the Shōwa era in 1926, and also the longest serving, in terms of number of tournaments, a record he holds jointly with Chiyotaikai.