There has been many debates on this topic. Some argues that the correct way to punch is with the index and middle knuckles. Some debates that the right way is by using the last three knuckles.
The former school of thought is prevalent among the modern boxing and Muay Thai, as well as other well-known martial arts such as Karate and Taekwondo. The latter is make up of old school boxing (the Sulllivan/Dempsey era and the likes), Jeet Kune do by Bruce Lee and Wushu.
The former’s punch utilises standard horizontal punch we all know today, the way we punch when we were kids, when some drunken idiots in the bar deserves it. The latter is using the vertical punch for their hand attacks. In this article, I will be using the standard horizontal punch for sake of discussion.
I have tried both. I started learning boxing and Muay Thai by punching with the first two knuckles. Then I read up Jack Dempsey book Championship Fighting and Bruce Lee’s Tao of Jeet Kune Do and tried the latter.
Both have their pros and cons. I myself prefer punching with the last three knuckles. Although some may argue that this way punching might cause the pinky (the last finger) , which is the most fragile finger in our hand, to sustain injury. The correct way to punch with this method is by concentrating the impact on the middle and ring fingers. So far after 2 years training this way, I had yet to sustain injuries on my last finger.
I prefer this punch is because the alignment of my bone from forearm to the wrist feels more natural when it hits the target. When using the first two knuckles, the wrist will bends slightly anti-clockwise if you are throwing a right.
In the near future, I will discuss the vertical punch vs the horizontal punch which utilises the different knuckles to punch as well.