Tim Jester wrote:
Uke plays an important role in this, and he has to know what reaction is appropriate for the technique your working on.
Of course, this is in kata, which is a prearranged learning tool. Eventually you must learn to feel and be sensitive to human actions to recover their balance. It is actually very predictable since we're bipeds. Through the connection (ki musubi) we know what our uke is doing and where they'll step next and we fit our waza to those recovery actions. This is why training systems need a "feedback loop" that is not programmed. Randori or sparring serves this purpose. Randori in my mind means to take something of form out of chaos.
Staying connected, making intuitive, creative decisions on the go while controlling the initiative and taking part in waza that solves problems is juicy practice.