Basic fighting skill would only suffice if the knife wielder is very incompetent. A bad guy carrying one probably has at least a little competence. Knives are dangerous for the reason below: Unlike a punch, a knife stab or slash needs little power to be effective. Even using proper body mechanics, a good puncher needs a half foot to a foot distance to generate dangerous power. And that's being generous. A knife just needs - none. It just needs to make contact. Then, a flick of the wrist is capable of inflicting damage. Anyone who underestimates the danger of a knife will end up losing blood or their life.