Re: does nikyo hurt?
I am learning that there are a couple sorts of hurting in aikido. Nikkyo is an excellent example of this dichotomy.
There is the nikkyo where nage is twisting and squeezing and wringing the shit out of uke's wrist. Iit hurts like a son of a bitch, it can even injure uke, but it does not break uke's structure down and uke can find the place to resist, absorb, reverse, or neutralize the technique.
The nikkyo I hope to learn before I die is a little different. The emphasis is not on pain compliance, but on kuzushi. The nikkyo is applied in a way such that uke loses their balance in such a way that they fall into the nikkyo, they put it on themselves with their bodyweight This makes a very strong, fast feedback loop, and this nikkyo goes from being just about kuzushi, immediately through any mere idea of simple "I'm gonna hurt you unless you do what I want you to" pain compliance, to an agony of having no structure, no balance, and this weird, white-hot inescapable sensation that is just a dozen notches up from pain.
The first nikkyo hurts, but that's about it. The second nikkyo destroys uke's structure, and oh by the way hurts a bit, in a way that locks up and hurts more than just the wrist, and there's not a damn thing uke can do about it.
The difference to my noobish mind is that the nage doing the first nikkyo is doing it in a way that sends the forces into the wrist, and then into the uke's center so that uke's legs, pelvis, center, spine, shoulder and arm can all absorb a little bit of the discomfort, and all the joints have some degree of freedom of movement. The second nikkyo looks much the same, but the energy put into the wrist is brought in front of uke, toward a front "third leg" that causes uke to fall forward into the technique.
This seems to me to be a concrete example of using uke's energy against them.