Which of the following belts is not recognized in the ranking system of Judo?

Explanation

Judo was created by Jigoro Kano in Japan in 1882 and became an Olympic sport at the 1964 Summer Olympics in Tokyo. In Judo, Dan ranks (black belt levels) indicate technical proficiency and contribution to the sport: 1st–5th Dan (Shodan–Godan): Solid black belt. 6th–8th Dan (Rokudan – Hachidan): Red and white belt (Kohaku - obi). 9th–10th Dan (Kudan–Judan): Solid red belt.