Centerline theory involves an imaginary line that extends vertically and divides the body into two bi-laterally symmetrical halves. The centerline is important because many vital pressure points lie along it (both front and back), such as the brain, throat, heart, solar plexus, bladder, testicles, or the spine. By shifting your centerline with respect to your opponent, you may make it less accessible and less vulnerable to attack. Your guard and blocks should protect your centerline.
The opponent's centerline serves as the convergence point of your strikes. Attacks should be directed toward the centerline. Do not extent your attacks and blocks past your own or your opponent's centerline or you will expose your side and rear to attack. Not extending your strikes and blocks to the centerline opens your centerline to attack.
If one can control the opponent’s centerline, then his ability to effectively move and strike will be nullified. Thus, understanding centerline theory and applying it in practice can greatly enhance one’s ability to strike and to defend.