Gunji Koizumi
 Gunji Koizumi (小泉 軍治 Koizumi Gunji 8 July 1885 – 15 April 1965) known affectionately by colleagues as G.K. was a Japanese master of judo who introduced this martial art to the United Kingdom and came to be known as the 'Father of British Judo.' He was the founder of the Budokwai a pioneering Japanese martial arts society in England. Koizumi helped establish the British Judo Association and founded the European Judo Union. He held the rank of 8th dan in judo.