Re: The shoulder grab - where does this come from
The push or pull in katadori is clearly evident on my Yoshinkan videos. If pushed, tenkan, if pulled irimi.
I have always seen that the gi was grabbed. I can't see bring controlled with just a hand on the shoulder. I have always been taught that the shoulder grab was a prelude to another attack. Grab the shoulder to prevent the victim from running away from the other attack.