Ignatius Teo wrote:
,,,the specific way in which ukemi is performed - not as a means of falling over or escape, but as a means to condition the body in this manner - could be viewed as a legitimate method for kokyu development, or at least the start of it.
That's pretty much what I'm saying. Plus, it's using kokyu--not just developing it.
On the other hand, as aiki is the ura of kiai, ukemi is the ura of aiki waza. Mochizuki Sensei had to take pains to explain to me that ikkyo is not meant to roll the oponent away, but to plant him into the floor, face-first. Likewise most of the other techniques. They're not intended for the uke to roll out of, but ukemi can be a way to escape a technique--or even turn it into your own sutemi waza.
Of course, Dan's major point is that it's better not to be gotten in a technique to the point where it breaks the structure enough to force you to fall, but as Mike said somewhere, it's realistically a sliding scale. You can develop great abilities, but so can the other guy and there's a point where size and strength, combined with skill and technique, can overcome us.
I'd like to point out again, as well: Mochizuki Sensei was uchi deshi to Kyuzo Mifune. We can look at "Master of Judo" and see that all his ukes were trying to throw Mifune and also doing their best not to be thrown by him. As powerful as they would be to an ordinary person, they couldn't stay on their feet against Mifune.
And Mochizuki Sensei was also uchi deshi to Morihei Ueshiba, who was able to throw Tenryu on contact. So I don't think it's surprising that I should find it sometimes difficult to stay on my feet when dealing with people who had trained with him for over twenty years. I found strong ukemi skills invaluable in that situation and I had to use kokyu in those ukemi as much as in nage waza.
Ignatius Teo wrote:
The other thing I would posit is that ukemi might start out as big, expansive movements when first learning, but as one gets better at receiving force, ukemi becomes less external and more internal, IOW, motion approaching stillness.
Again, I agree with that summary. However, I like to teach ukemi from very small movements in the beginning, then build them up to fairly large movements, then let the student learn through practice to make them smaller and smaller.
Best to you.