The official rules of boxing
Here is a list of what is legal and illegal in boxing according to the official rules.
Hitting someone in the leg: illegal
Hitting a man in the ears, neck, and face as hard as you can, over and over again, for forty minutes straight: legal
Elbowing someone in the stomach: illegal
Hitting someone so hard in the head that part of his brain dies: legal
Grabbing someone’s gloves to stop him from hitting you in the face for a few seconds so you can take a breath and think things over like a reasonable person: illegal
Punching someone so hard in the eyes that blood shoots out of his eyes, ears, and mouth and he dies right there in the ring: legal
Wrapping your arms around your opponent to try to get him to stop murdering you for just a couple of seconds: illegal
Hitting someone in the brain so hard, over and over again, that his brain stops working and he becomes unconscious. Then, the second he regains consciousness you start hitting him again, in the same part of the brain: totally legal