<P> John Saxon is a black belt in Judo and Shotokan Karate, who studied under grandmaster Hidetaka Nishiyama for three years . In negotiations, his agent told the film's producers if they wanted him they would have to change the story, the character of Williams would be killed not Roper . They agreed and the script was changed . </P> <P> Rockne Tarkington was originally cast in the role of Williams . However, he unexpectedly dropped out days before the production was about to begin in Hong Kong . Producer Fred Weintraub knew that karate world champion, Jim Kelly had a training dojo in Crenshaw, Los Angeles so he hastily arranged a meeting . Weintraub was immediately impressed with Kelly and he was cast in the film . The success of Kelly's appearance launched his career as a star: after Enter the Dragon, he signed a three film deal with Warner Bros and went on to make several martial arts - themed blaxploitation films in the 1970s . </P> <P> Jackie Chan appears as a guard during the underground lair battle scene and gets his neck snapped by Lee . He also performed several stunts for the film, including the scene where Lee's character quickly climbs a rooftop at night . However, Yuen Wah was Lee's main stunt double for the film . </P> <P> Sammo Hung appears in a brief fight scene against Lee at the start of the film . </P>

Was jackie chan in the movie enter the dragon