I agree - a punch should come from wherever your hands are; you shouldn’t have to wind up or cock your fist to throw a punch. And in a fight, I know my hands are going to be covering my head and chest if they don’t have anything else (like covering) to do.
It’s been a long time since I took karate (kempo, if you’re wondering), but the fighting stance we used the most had the body tilted away from facing the enemy, preferably with the stronger arm near the back and the weaker arm to the front. The sideways stance helps to protect your center line (the line of targets up your front, from the groin to the face) and gives you more distance to build up momentum in your strong-arm punches. The weaker hand is primarily used for blocking, but can also be used for attacks if the opportunity presents itself (usually an elbow strike or hammer fist, rather than an actual punch, due to having less room to swing. The stronger hand doesn’t actually start off by your hips, but at about the bottom of the ribcage.
Of course, as bauble points out, this doesn’t mean too much once the actual punching starts; you have to be able to do something from any position you might find yourself in. Of course, in many of those positions, a punch won’t be your best option, anyway.
If you want to see what kind of punches work best most often, just watch professional fighters. They have a lot of motivation to punch effectivley (they’ll get their asses kicked if they don’t), and much more experience than a lot of MA instructors.
Chan’s dojo straight reverse punch technique might indeed be 3.12% more powerful than Phil the Crackhead’s dark alley hay maker, but Phil will still kick your ass and steal you wallet since he’s a better fighter than you.
All different kinds of punches work, there is no “best way” to punch all the time, and the prefered way to punch depends on what the other guy knows and does. Naturally you’d get even more out of you time by learning how to survive in more than one dimension of fighting.
I think the real purpose of the twist is to protect your wrist in the event of your punch not getting through because of a hard block. Punching with your palm down through the whole motion seems to me like a good way to sprain your wrist.
Your punching bag isn’t going to interupt your blow before you want it to.
This only applies for a standard straight punch from the waist.
This depends on the martial art. Karate is very counterintuitive in some ways and it’s difficult to get beginners to move in the prescribed form. Aikido is relatively natural in its movements. Wing-chun is a pretty extreme example of a highly specialized posture. Various martial arts have very different movements from the way most people move, others are very close. When I first began taking martial arts, I was taught to punch with the use of two analogies: 1) Turning on a light switch, 2) Pushing a heavy object.
The light switch analogy prompted you to stop leaning into the punch so much or overreaching, the way most beginners do, while the heavy object idea got you to brace yourself reasonably close to the position you should be in for maximum power at the end of the punch. Within a couple of days of learning to punch that way, the movement was integrated into my normal movement. It felt so natural and balanced that not moving that way felt weird.
I had to consciously change my movement when I opened doors so I didn’t slam them open. That stayed with me even when I hadn’t practiced for years. At my college, some of the doors were solid core wood about two inches thick, twice as wide and a bit taller than a normal front door for a house. When I was in a hurry one time, I wasn’t paying attention and I hit one of those doors so hard that even with the pneumatic arm slowing it down, it broke the doorstop and partially imbedded the doorknob in the stucco-faced concrete wall behind that. I felt pretty stupid and was very glad there was no one on the other side.
Years later, I saw a video clip of Bruce Lee demonstrating his one inch punch and saw a lot of similarities between the way he moved and the way I was taught to punch.