We did not do much in the way of joint locks, but we did work on nikkyo a little. Mike reinforced to me that it does not work without positional dominance, moving or pain. He could ground out the technique and bounce me back. I could do the same, that is ground out the technique, although I could not bounce it back. Regardless, you were not going to get Nikkyo.
Just to clarify a little, I was only using a limited approach to nikkyo as one of the examples to teach people to bring jin/kokyu-power where they wanted, at will. We also did "unbendable arm" and a few others simply to get people used to bringing jin where they wanted it. The actual challenge strength to the body was not enough to say that we seriously attempt an attack. I.e., it was just a training thingy.