Koji Shibamoto is a judo and Brazilian jiu-jitsu black belt under Mitsuyoshi Hayakawa, widely regarded as one of the main competitors of his generation's roosterweight division. A former athlete for the Tokai University judo team during his early adulthood, while also representing the country of Japan in international judo tournaments, Koji Shibamoto turned his focus to grappling during the mid-2000s, quickly becoming the most acknowledged Japanese competitor of his time.