Kotegaeshi is an entire group of techniques - not just a few common forms, as seen in the video I previously posted. Kotegaeshi is really most anything in which uke is curling his arm and tori is following. This can lead to throwing it by crushing into uke or moving away. Tori can catch it with otoshi or guruma timing. Virtually any floaing throw with uke's arm in a curling action can be called kotegaeshi.
This is not just a point of terminology. My point is that there are a lot of kotegaeshi forms between and beyond the few common forms practiced, and if our goal is to harmonize with uke in an aiki-like fashion then we have to be able to flow and execute the kotegaeshi that the uke-tori relationship calls for.
Here are a couple of kotegaeshi exercises that will improve your sensitivity to the kotegaeshi relationship:
- Face uke and take his right hand in a kotegaeshi grip with tori's left hand. uke relaxes and tori takes all the slack out of the arm without cranking it. Move uke's arm right up to the end of the range of motion of the shoulder, elbow, and wrist joints - but don't press it further. No pain. Now, here's the trick: Tori makes an unbendable left arm that still floats at the shoulder. Wherever uke moves, tori's left shoulder will float but there is still a one-sided restriction on uke's wrist, elbow, and shoulder and there is a motion restriction because of the unbendable arm. Ok so far. Here's where this gets cool: tori, take your right arm and palm-bump uke on the chest or shoulder or face or wherever. Doesn't have to hurt - just make uke vibrate or oscillate a little. As uke moves around to accomodate to the bump, float the left arm with them and take up the slack (still not cranking). See can you get uke to sit down and look confused because he doesn't really know why he couldn't stand up.
- Second exercise: face uke and take his right hand in kotegaeshi with tori's left hand as above. Take up the slack as before. Uke and tori begin stepping back and forth in synch (uke's right leg, tori's left) while the other feet remain planted. Watch for the time that uke sets the moving foot down in front and tori, stretch your step. Make uke think you're going to step down with him but float your left foot farther in time and space after his foot lands. You can stretch by stepping closer to uke's center, down the line of his feet, or by retreating away from uke's center. Watch to see if you can get uke to pop up onto his toes.
I'll have to try to get some video of these two exercises to post here, but if you try to work through the text descriptions above you can probably play around and get them pretty close to right. These two exercises - taking up the slack with a floating unbendable arm, and stretching the step after uke plants the moving foot - will make a world of difference in your sensitivity to which kotegaeshi uke is trying to fall for.