Fairfax, Va., solo David Z. Kaufman may have the only Web site devoted to martial arts law, KarateLaw.com. A sixth-degree black belt, Kaufman counsels karate instructors and students on liability, contracts and a host of related issues. He also serves as an expert witness in cases involving the martial arts. I was ready to proclaim him the only lawyer in the field, but then I found Randall R. Sevenish.