Joseph Henry Lewis, 68, of Wayne, a karate grand master and kickboxing champion who developed a martial-arts training system, died Friday, Aug. 31, of a brain tumor at Coatesville Veterans Affairs Medical Center. Mr. Lewis, a 10th-degree black belt, was U.S. karate champion from 1966 to 1969. In 1971, he retired as undefeated U.S. heavyweight kickboxing champion. He was featured in both the Ring, a boxing magazine, and Sports Illustrated. In 1975, Mr. Lewis was inducted into the Black Belt Magazine Hall of Fame. He studied with martial artist Bruce Lee and assisted Lee with fight choreography for his movies. Mr. Lewis also starred in several action-adventure movies: Jaguar Lives, Force Five, Death Cage, and Mr. X. He was featured in other films and appeared in television series and as a guest on talk shows. Since 1984, he had traveled the country giving seminars on his Joe Lewis Fighting Systems.Dennis Nackord, who operates Nackord Karate in Wayne, first trained with Mr. Lewis in San Mateo, Calif., in 1968. "He was my mentor," Nackord said. "Joe was a pioneer, forging what martial arts are today. He was known as the Muhammad Ali of the sport." David Shaw attended seminars with Mr. Lewis at Nackord Karate. "He was incredible to watch," Shaw said. "His fists were like cinder blocks - literally flattened out from all of the punching - and his speed just amazing. He was notorious for his side kick and told us he perfected it early in his career by throwing hundreds every day." After being diagnosed with cancer last year, Nackord said, Mr. Lewis was visited by many of his friends from the martial-arts world, including Chuck Norris, who arrived by private jet. Mr. Lewis grew up on a farm in Wilmington, N.C. He enlisted in the Marine Corps in 1962 and was stationed in North Carolina and in Okinawa, Japan, where he discovered karate, earning his first black belt in just three months. In 1965, he was deployed to Vietnam as a member of the Eighth Marine Brigade and taught hand-to-hand combat to a reconnaissance unit. He began competing professionally after his discharge.