Re: Ukemi and Kokyu
I think kokyu is an important part of balancing the quickly-changing forces exerted on the body as it translates vertical momentum to horizontal momentum and returns to standing. The force of the kokyu must vary with the force on the body at different points of the fall or roll, and also with the degree of force in the throw.
However, I also think that the root comment for this thread is that the best way to experience kokyu is to take ukemi for a master.
For those of us who can still be thrown by a real master, it takes excellent falling skills, which are all that allow us to repeatedly experience such a master's technique.
So ukemi allow us to experience a master's technique and kokyu and also give us a chance to exercise and develop our own kokyu. And, having felt the master's kokyu, we can put more of that into our ukemi. Developing it thusly in ukemi, we have better kokyu to use in techniques as nage.