What is the purpose of Oi-Tsuki?

Oi-tsuki or as some refer to it in English as the lunge punch is thought by some as the most powerful punch since you place the momentum of your entire body weight behind the punch. It is done with the rear hand doing the punch as you step forward with your rear foot all the way from behind you to all the way in front of you and is a means of extending your reach and being able to hit someone.

It is one of those techniques that requires total commitment and so employing it at the wrong time can result in dire consequences. It was not meant to be used against a mobile, aggressive type adversary but instead one that is hurt and/or stationary or who is retreating. Against a mobile, aggressive type adversary there is too much chance of them stepping out and catching you part way forward or maybe even with the other foot even and you wide open with your body facing fully forward and more exposed.

Oi suki can be devastating because it uses what I like to put in caps, WHOLE BODY ENERGY. The entire weight of the body goes into the strike. Now you might be thinking, how can a 60 year old, defend himself against say a 20 year old. Well if the weight of the entire body goes into one area of the opponent, he's going to drop like anyone else. I have also seen a very similar movement in Xing Yi. It is amazing how many techniques and concepts can be found in various styles. In Xing Yi, it is a take down, as the forward movement of the body along with the thrusting move of the punch can be used in a sweeping motion. There is a hidden move behind every punch and technique, you just have to find it. Your questions are thought provoking.

Oitsuke is a pursuing punch and allows you to gap close and use the linear acceleration to lay into your opponent. If you do it right and not move your hands too much, the opponent will think you're moving slower than you are. Don't worry about grabbing the opponent - use the opposite hand to trap or control. Continue with the forward pressure and follow through with additional strikes. Enjoy! :-)