He has an 8th Dan black belt in World Karate Organization Shinkyokushinkai.

[1] Midori was a student of Mas Oyama, the founder of Kyokushin kaikan.

Four years later, Midori entered the 5th World Tournament, where he defeated the reigning All Japan Champion Akira Masuda to become the 5th Kyokushin Karate World Champion.

After the death of Masutatsu Oyama, the founder of Kyokushin Karate, the International Karate Organization (IKO) initially broke into three groups, one of which is known as IKO-2, initially led by Yukio Nishida.

Today, Midori holds the position of Daihyo (President) of the WKO Shinkyokushinkai (新極真会).