Geesink took up judo at age 14 and, by 17, started competing internationally, winning a silver medal in 1951. At the 1961 World Championships, Geesink, then 5th dan, became World Champion in the open class, defeating the Japanese champion
Koji Sone. Japanese judokas had won all the World Championship titles contested up to that point. Judo debuted as an official sport at the
1964 Summer Olympics, held in the sport's home country, Japan. Although Japan dominated three of the four weight divisions (light, middle, and heavy), Anton Geesink won the final of the open weight division, defeating
Akio Kaminaga in front of his home crowd. After winning the 1965 World Championships and a last European title in 1967, Geesink quit competitive judo. Anton Geesink was one of the few 10th
Dan grade judoka (
jūdan) recognized by the
IJF but not by the
Kodokan Institute at that rank. Promotions from 6th to 10th Dan are awarded for services to the sport of judo. In 2010 there are
three living 10th dan grade judoka (jūdan) recognized by Kodokan:
Toshiro Daigo,
Ichiro Abe and
Yoshimi Osawa. The Kodokan has not awarded the 10th Dan to anybody outside Japan. ==Professional wrestling career==