During the next 20 years, Mifune's reputation continued to grow. He became 6th dan (rokudan) in 1917 and 7th dan (shichidan) in 1923. When he was 40, he was challenged by a 6′ tall and 240 lb. sumo wrestler. Mifune, 5′ 2″ tall and 100 lb., finally slammed the wrestler with his trademark "airplane" throw ("kuki nage" or "sumi otoshi"). He ate sparingly, slept on a Western-style bed, and did not smoke. In 1931, Kano promoted Mifune to 8th dan (hachidan) and in 1937 to the rank of "kudan" (9th "dan").