Open Mind, in the booklet DEFENDING AND LEGALLY ESTABLISHING THE GOOD NEWS by Hayden C. Covington, you find the following points on Self-defense:
"The courts have held that Jehovah's Witnesses have the right to defend themselves when attacked by one who objects to their distribution of Bible literature."
(p. 80, XXII, B)
"If forced to use self-defense, do so. (See The Watchtower, September 15, 1939.)"
(p. 83, par. 1.)
The Universal Dictionary defines Martial art: "Any of several methods of fighting or self-defence, such as judo or karate, originated in the East." (p.946)