Re: What is good ukemi?
I agree with Jun.
I used to just want to avoid being open while taking ukemi. Then, I developed more flexibility and awareness and found it difficult to not to have those "fly away" too early tendancies. Now, I still work towards being more flexible and strong in the attack, and still not open (or I suppose less open). If I'm working with an atemi happy uke I usually will treat that like they are the uke and do a (reverse) technique. Something not usually mentioned but important about ukemi is getting up instantly and attacking again - lots of people kind of have a tea party on the mat between each throw.
The best uke I ever saw was in Takeda sensei's dojo. Takeda sensei was standing maybe 3 feet from a wall, and the uke (a 6th dan nicknamed "Mr. Aikido") came to attack like a freight train. Takeda sensei basically threw him up and back over his shoulder at the wall. I have no idea how he does anything so I can't describe the technique very well. The uke magically absorbed that energy into his body somehow and not only avoided splatting into the wall, but also landed, turned around, and instantly attacked again. All I could do was gasp. Takeda sensei laughed and started trying to throw him into walls - and couldn't. Then he started calling up other people and throwing them at the walls. Several of his ukes could avoid the wall too (though they didn't run in as fast as the first guy). I also got a turn. I bounced off of every wall in that dojo. (They weren't hard impacts, but I couldn't avoid them.) That was several years ago now, and although I made a lot of improvement, I still think I would be splatted into the wall given the same situation today.