Johannes Cornelius Bluming (born February 6, 1933) is a Dutch instructor of Judo, Kyokushin Karate, Hapkido, and mixed martial arts. He was the coach of two-time Olympic champion Willem Ruska.Born in Amsterdam, he was 16 when he applied for the Marines and was accepted to the bootcamp in Doorn in July 1949. In the summer of 1950, the Korean War started, and he applied as a volunteer in the van Heutz regiment. When he was wounded, he was transported to a Japanese hospital in Tokyo.