 For his achievements in training OSS personnel, Fairbairn eventually rose to the rank of Lieutenant-Colonel by the end of the war, and received the U.S. Legion of Merit (Officer grade) at the specific request of OSS-founder "Wild Bill" Donovan.After joining the SMP, he studied boxing, wrestling, savate, Shin no Shinto ryu jujutsu (Yoshin ryu) from Okada-sensei, Kodokan judo in which he gained a 2nd dan black belt, and then Chinese martial arts.He developed his own fighting system—Defendu—and taught it to members of that police force in order to reduce officer fatalities.