Armpits, groin, sides of the neck, insides of the forearms. Major blood vessels close to the surface.A small blade cuts shallower do to decreased cutting surface and length requiring a knowledge of vital areas, as well as a techniques for reaching them with decreased reach.
Unloved has the right idea. A 3 inch blade possesses all the fighting utility you need in a self defense knife. A larger knife is slower, clumsier and the target selection/damage ratio is the same. Even a full stab through the torso with a 7 inch blade is not a guaranteed fight stopper. Work the outer appendages, disabling them with quick multiple cuts and the altercation will be over pretty quick. Besides, which knife would you rather have presented to a jurybox full of uninformed sheep, your 12" vulcan death dagger with the skull pommel or your diminutive little Delica that you use to peel apples for your GrandChildren?Armpits, groin, sides of the neck, insides of the forearms. Major blood vessels close to the surface.