Knockout blows
Having researched knockout techniques I have found that apart from the holds and grabs that constrict major arteries to the brain, the type of blow most likely to cause a knockout is a sharp, explosive blow of which the force is channeled into the opponent's body, causing sudden trauma to the brain or heart. To develop such a blow takes the right kind of practice. It already takes a lot of concentration to execute such a technique from a grounded position, like one would do during form practice. So- it will take even more practice and clarity of mind to execute such a technique in a real fight. To give you an idea of the blow you are looking for, take a bucket of water. Then punch into the water with the intent to have as much of that water splash out with one blow. Keep punching until the bucket is almost empty. :)