Safety first, they don’t teach jiu-jitsu in the emergency room.
The safety principle is fundamental our jiu-jitsu training. Don’t get hurt, and don’t hurt each other. There’s one obvious reason: pain sucks! And that’s reason enough, but there’s more to it–the ability to practice realistically and verify our skills.
Practical PracticeChad Morrison sums the idea of practical practice up wonderfully in his article on the Akari Judo blog for June 30, 2011.
The biggest genius of Kano, I think, was that he could make a more effective martial art by removing the most lethal/damaging techniques. The eye gouge is an amazingly effective way to end a fight, sure, but you only get to practice it at most two times with your partner – and even then you have to be pretty persuasive to get that second rep in. You can fake it – go right up to the point of gouging the eye – but because you can’t practice an eye gouge in a live situation, your ability to pull one off in a real confrontation would be in question. So Kano took those techniques that he felt could not be safely executed in a live situation, and he gave them the boot…
What you are then left with is a martial art where you can go all out with your full range of techniques (or, in the case of submissions, until they tap, and you simply have to disregard the tap to finish the technique). Now, you can attempt to apply your knowledge against a resisting, moving, and attacking opponent, without fear of breaking him or her. And by getting to practice in this live situation… over and over and over again, you are now much more likely to be able to apply your knowledge in a “real” encounter. So by taking out the “effective” techniques, Kano made Judo more effective. Genius!