Your story about your Kokyu Dosa partner brought back some memories for me!
When I was just a green nikkyu, I would get paired with this one gentleman in Los Angeles who would grip my wrists, sit calmly and smile. He would not do anything to counter me or "trick" me. Most of the time I felt as if I would stand a better chance with a 3'x3' brick wall!
Kobayashi, Sensei, would come over and show me what to do. He would stand and watch and coach, and slowly I began to improve. At least I began to take this man over maybe once every ten times. One day he and I paired up and as soon as he grabbed, I smiled back and took him down. At that point he smiled at me and went to someone else. My lesson was done. Of course this took roughly a year or so for that to happen.
No moral here (really!), just a fond memory of early frustration with Kokyu Dosa.