It is bias to think that the art of war is just for killing people. It is not to kill people, it is to kill evil. It is a strategem to give life to many people by killing the evil of one person.
When you strike a blow, do not let your mind dally on it, not concerning yourself with whether or not it is a telling blow; you should strike again and again, over and over, even four or five times. The thing is not to let your opponent even raise his head.
A stroke of the sword that does not hit its target is the sword stroke of death; you reach over it to strike the winning blow. Your adversarys inititive having missed its mark, you turn the tables arround and get the jump on your adversary.
See first with your mind, then with your eyes, and finally with your body.