Frank William Dux is a Canadian-American martial artist and fight choreographer whose self-professed life story served as the basis for the 1988 film Bloodsport. Born in Toronto in 1956, Dux claims he was trained as a ninja in Japan by a master named Senzo Tanaka, and that in 1975 he secretly participated in and won a clandestine, full-contact mixed martial arts tournament called the Kumite, held in the Bahamas. He further asserts that he set multiple world records during the tournament, including the fastest knockout and most consecutive knockouts.
Dux's extraordinary tales first reached a wide audience through a feature article in the November 1980 issue of Black Belt magazine, where he detailed his experiences in the supposed underground fighting circuit. He later expanded on his life story in his 1996 memoir, The Secret Man: An American Warrior's Uncensored Story, which also included claims of working as a covert operative for the Central Intelligence Agency on secret missions in Southeast Asia.
Virtually all of Frank Dux's major claims have been heavily disputed and widely debunked. Investigations by the Los Angeles Times and other outlets found no evidence for the existence of the Kumite or his ninja master, and his military records show he never served overseas or received the medals he claimed. Despite the controversy, his colorful and unverifiable story captured the imagination of screenwriters and became the foundation for a cult classic martial arts film, cementing his bizarre legacy in pop culture.