Re: Locking/pinning as pain submission...
Perhaps that's why the Aikikai folk often won't acknowledge Rokkyo...
Personally I have no problem inflicting (and recieving) pain during training - my original point was directed more towards the intent.
Here's how I view it:
If I lock someone's body up and control them, I'm happy.
If I lock someone's body up, control them, and inflict agony - SCORE.
If I just inflict agony - I screwed up.
As for all this "natural motion of the wrist" crap - you guys are WAY overanalysing things (seems kinda common around here). He knew what he was trying to say, but may not have been able to put it in writing properly - who knows. Fact is, all joint locks, by the laws of physics (and therefore biomechanics) work in the same way, by moving joints beyond the normal range of motion and either hyperextending, or compressing the bone structure. This is indisputable fact. I'll even challenge anyone to think of a joint lock which doesn't involve hyperextension or compression from _any_ martial art.
Also, it's important to note that just cos someone wrote something in a book once, does not make it true. Look at O-Sensei, he claimed he could dodge bullets - a blatantly false statement - and probably not what he meant (more something along the lines of he thought he could blend well enough with the shooter to be able to move before the trigger is pulled, but after the shooter has comitted to the shot - very highly unlikely, but I suppose not physically impossible - depending on range and target).
The overanalysis of things is pretty common, just take any religious text from just about any faith and you'll find the same thing, a bunch of dedicated people who have made the study of something their hobby/life's work and through their eagerness to get every last bit of information out of something begin to lose perspective. Language cannot transfer an idea from one person to another perfectly, it can only transfer an approximation of an idea. Sometimes the approximation is close, other's it's hardly similar at all. Language is best known to fall over when dealing with complex, abstract ideas.
In other words, if someone says something that is clearly ambiguous or wrong, chances are they're either flat out wrong, or trying to express something abstract that doesn't quit fit into words and they've picked the next closest thing.
In summary (for those who can't be bothered reading all that), regarding the "natural motion of the wrist" fiasco, I believe that it was meant in either the abstract, or was a miscommunication/misunderstanding.