Self-defense, for example, is an affirmative defense: "Yes, your honor, I committed an act that satisfies all of the elements of the crime (assault, aggravated assault, manslaughter) but it was justified because..."
Physical self-defense, counter-assault, is breaking the rule against doing harm to others.
That's a tangent.
Over on Patrick's blog, he writes about stiff-arming in judo. It is a beginner's mistake, but it is a really hard habit to break. It is a hard habit to break because it works.
It occurred to me this morning that when a beginner stiff arms and blocks a throw, it is a bad habit. Poor judo. When a skilled practitioner blocks the same throw in the same way it is "good structure."
What else does this apply to? It's subtle, the first thing that comes to mind is the manhandling drill. Being thrown around really messes with people, until they learn that it is all a gift and suddenly danger becomes opportunity. That's different, though, because usually what the beginners try doesn't work.
What are the things where beginners are effective, told to stop being effective because it is bad X or whatever, and then later are either taught to do it again under a different name or just notice that the senior practitioners do it?
I know of 'chi masters' in internal styles that state that they don't move and their students seem incapable of seeing them move... but they clearly do. There are weapons instructors who state emphatically that the hands (or weapon) must lead the feet, must move first. But those instructors never actually do that. Their hands and feet move together. The student has no hope of matching speed or coordination or power until they reject what the teacher says and do what he does.
It's curious. A fun thing to think about. I don't think it's deliberate, except in a few cases. The instructors aren't trying to hamper the students. In some cases it does make sense. The stiff arm in judo works very well defensively, but it gets in your own way offensively and hampers sensitivity. It works, but it really gets in the way of internalizing ju.