Judo Trivia

John Halloran is the evil Capt. Oshima who has the great judo fight with Cagney. Halloran's real name was Jack Sergel.
From Mas Uchima and Larry Kobayshi, "Fighting Spirit: Judo in Southern California, 1930-1941," 2006, one finds that Sergel was part of the San Fernando Dojo in 1932. He later trained at Rafu and Seinan, which were downtown, and during the 19th Grand Judo Championship (Fall 1939), he set a record of five wins while a kyu-graded competitor in the tournament's red/white competition. He also appears in the workshop photo of 1939, the one at which Sumiyuki Kotani was the guest instructor. By 1941, he was graded 2-dan through Nanka Yudanshakai. He kept Seinan open during Relocation, and during 1944-1945, he took Caucasian students, including some women and a Budokwai member, to the Relocation Center at Manzanar for purposes of getting his students graded in judo. He also took his club to competitions in Manzanar Interment camp during WWII. Halloran/Sergel was in the LAPD. Halloran/Sergel resigned from the LAPD after the police commission sent FBI agents to investigate him because his favorite sport was judo. James Cagney - who needed to learn Judo for his movie Blood on the Sun contacted him and asked him to teach him Judo. Halloran went on to play in many more movies including Angel and the Badman with Gail Russell and John Wayne.