Lee demonstrated his Jeet Kune Do martial arts at the Long Beach International Karate Championships in 1964 and 1968, with the latter having higher-quality video footage available. He demonstrated his fast speed, launching quick eye strikes before his opponent can block. Lee then performs "chi sau" while blindfolded, probing for weaknesses in his opponent while scoring with punches and takedowns. He then performs the one-inch punch on several volunteers. Lee then participates in a full-contact sparring bout against an opponent, with both wearing leather head gear. Lee can be seen implementing his Jeet Kune Do concept of economical motion, using Muhammad Ali inspired footwork to keep out of range while counter-attacking with backfists and straight punches. He also halts his opponent's attacks with stop-hit side kicks and quickly executes several sweeps and head kicks. The opponent is never able to connect with a clean hit, but once manages to come close with a spin kick. The fight footage was reviewed by "Black Belt" magazine in 1995, concluding that "the action is as fast and furious as anything in Lee's films."