By applying the impact force onto the smallest target area, it will concentrate the force and therefore increase its effect. For example, the force of water coming out of a water hose is greater if the orifice is smaller. Conversely, the weight of a man spread out on snowshoes makes hardly any impression on the snow. The blows in Karate are often concentrated onto the edge of the open palm or to the crook of the fingers.

 

It is very important that you should unleash your strength at the beginning, and gradually, particularly at a point of contact with your opponent's body, the force must be so concentrated to give a knock-out blow, that is to say, the shorter the time for the concentration, the greater will be the power of the blow. The utmost concentration is required in order to mobilize every muscle of the body onto the smallest target area simultaneously.

 

In conclusion, concentration is done in two ways: One, is to concentrate every muscle of the body, particularly the bigger muscles around the hip and abdomen (which theoretically are slower than the smaller muscles of other parts of the body) to the appropriate tool to be used at the proper time and the second way is to concentrate such mobilized muscles onto the opponent's vital spot. This is the reason why the hip and abdomen are jerked sharply in any action whether it is attack or defense.