Martial artists can learn a lot from people who have mastered different realms of combat because often the principles and tactics they use can be adapted to what we do. Case in point:  Oswald Boelcke. This German flying ace was one of the top innovators and instructors in the Axis air force during World War I. Among his many accomplishments, Boelcke chose a young Baron Manfred von Richthofen to become his pupil and coached him to an astonishing string of air victories. Von Ri

Fighting skill is one of the most unconventional abilities to quantify.