Striking and attacking the pressure points of the human body is a
very dangerous and effective form of fighting that will require
a much deeper understanding and commitment from the practitioner. The
study of pressure points, also known as vital points and kyusho points,
dates back thousands of years to China and there are some
excellent modern translations of ancient manuscripts that detail
this practise in depth. One such text, worthy of reading, is Patrick
McCarthy's translation of "Bubishi" the bible of karate.
Pressure point fighting uses the bodies energy meridians to control the opponent and when executed in accordance with the ancient Chinese five elements cycle of destruction (Wood, Water, Fire, Metal and Earth) can produce immediately devastating results. Kata, being a physical mnemonic of an effective fighting system, would contain practical methods and principles that would form the foundations of the bunkai.Understanding pressure point fighting derives from the investigation and study of the application of these methods and principles.
All kata bunkai, when truly understood, contain kyusho or pressure point striking techniques and if forced to defend yourself the focus is on the targeting of these vital points of the body, by utilizing sound techniques that will be practical in a variety of situations. However, knowing where these pressure points are in the dojo and then being able to attack them during the adrenalin charged chaos of a real live fight are two different things.
It is for this reason that it is probably, for practical reasons, best to concentrate on just a small number of known weak areas of the human body. You should also understand that kata bunkai, when attacking pressure points, would rely on a predetermined response. For example jabbing towards the opponents eyes would cause him to either grab your wrist, or move his head back away from your fingers. In the later case this would open up the weak areas of the throat and neck, allowing you to attack the carotid sinus and the pressure points along the side of his neck.
A sound knowledge of the vital points located on the body's extremities can prove to be a valuable asset in any self-defense situation. However, one must be aware of the severe consequences that could result in attacking some vital or pressure points on the human body, and the accountability that would result from this action.
To further your knowledge of pressure points and how they relate to kata bunkai, the following two books are recommended for reading and study:
The Bible of Karate: The Bubishi
Pressure-point Fighting: A Guide to the Secret Heart of Asian Martial Arts
