Charles Nelson joined the Marine Corps in 1934 and learned hand-to-hand combat, bayonet fighting and jiu-jitsu from, among others, Colonel Anthony J. Drexel Biddle. From Sergeant Kelly, who had been attached to the International Police in Shanghai, China, in the 1930s, he learned a unique fighting method based on Mongolian wrestling techniques intended to maim or cripple, which no one else in the United States was teaching at the time.