The One Inch Punch was made famous by Bruce Lee in the 70’s. It is an example of “short power.” This name is sometimes used to refer to the “three inch punch” which is basically the same thing done from one finger’s distance rather than one knuckle’s distance.
There are many explanation and demonstrations of this technique, but many of them are incorrect. For example:
The one inch punch has nothing to do with chi or internal power or anything else along those lines. It is simply a matter of proper body mechanics, leverage, and strength. The entire body is used together to produce a lot of force over a short distance. Martial artists always say that your power comes from your hips, and this is no exception. The technique does not use just arm strength, but uses nearly every muscle in the body, from the legs, to the hips, to the shoulders, forearms, and hands, each muscle group magnifying the strength generated by the previous muscle group. They’re not shooting chi through their hand or anything like that. It’s all body mechanics.
If you are watching demonstrations of the one inch punch online (there are many on youtube), please watch them in slow motion, if possible, because many people “cheat.” They will get everything set up correctly and move their hand back and forth a few times to show you the distance, but then when they actually do the punch, they pull their hand back a lot further than one inch, which they sometimes disguise by moving their entire body forward or performing some other distraction technique. It all happens quickly so most people don’t notice it.
Watch Bruce Lee’s original demonstration of this technique. He doesn’t take a step forward. He doesn’t quickly pull his hand back 12″ before delivering the punch His hand goes directly from a few inches from the target, into the target. A true one inch punch.
In the future I will try to post a vid demonstrating some of the ways that people fake this technique in their demo videos.