If you want to knock out somebody Karate is a good tool, but it does take a bit of understanding.
85% of the people throw a right hand to the face. This is usually an ill conceived round house punch, and it is predictable and easily blocked. So you set up for a good, hard punch to the face, and then you drive a straight line to the gut.
Mind you, this is a thrusting punch, and you want to lock your arm and go all the way through the fellow.
Most fellows don’t have great conditioning, and so the body support system collapses, and they are down, and can even be totally unconscious. It takes a heck of a wallop, but it can work. Practice driving your punch through a heavy bag every day for an hour. Get the idea that you can’t be stopped. Watch the bag bounce away.
The other and more sure knock out, is the punch to the head. When you punch the head you are trying to rattle the brain inside the skull. To actually make it slosh back and forth so hard it flattens out on the inside of the skull, and the fellow you hit drops unconscious.
And, yes, you can thrust through the head, the same as if you thrust through the body.
But, the better method is the light flick of the karate fist. It takes no energy, is mounted by a single clear and concise thought, and it describes the ‘invisible punch,’ that Mohammed Ali used to knock out Sonny Liston. People thought that the punch didn’t connect, that Liston took a dive, but, really, Ali just flicked a fist effortlessly, you can see Liston’s head duck down slightly, and then he is just falling.
To do this punch you have to be light and effortless. You should hang a speed bag and float by it, and just snap your hand like you were snapping a dish towel. You want the bag to rattle back and forth like rocks in a can. The fellow won’t see it coming, or he will dismiss it as lightweight because there seems to be no mass behind it. But, when it connects, bingo, lights out!
In closing i will say that it takes work to make this kind of speed punch work, and I would recommend that one learn how to break bricks with good karate punches if they want to really master this karate technique.