I agree with Joe, but ummm.... a good Martial arts teacher will tell you that sparing is meant to be a time of learning. Much like being in a class room. It is okay to deal powerful strikes, but you don't want to hurt the person you are sparring, unless maybe you hold a grudge towards them, but still thats not the point. If you go out and focus on knocking the person out, it wont happen, first you should focus on control your arms and legs. Power is important, but whats more important is control, with control you can deal precise and hard strikes that are more likely to knock a person out.
1. use primarily the roundhouse (dollyeu chagi) kick to knock someone out. It requires the least skill and is easy to time. If you master the roundhouse, try the back hook kick (dwi hulleochagi). This kick is much more powerful but requires a good amount of skill and timing. But in many cases, it will miss the target. Or try teh side hook kick (yup hulleochagi.)
2. Aim to strike across the cheek or chin. Not the back of the head. By hitting the cheek or chin, your kick's impact will be able to deliver its power much more effectively. Plus, the cheek is a natural pressure points used to knock people out.
3. Try power kicks that hurt to submit or hinder the opponent. The back kick (dwi chagi) or side kick (yup chagi) are one of the powerfullest kicks in taekwondo. Trust me, once you can deliver that kick, the opponent will either fall over or be seriously winded.
Well the best bet you have are dollyo chaagis (roundhouses) or naryo chagi (axe kick) to the head
And if done with impeccable timming will definitely knock someone out cold in Taekwondo
Cheers
There is only one legal way: a kick to the head.
