Re: The shoulder grab - where does this come from
Certainly judoka consistently grab the shoulder [the gi area not flesh ] ,either 1.Pushing.2.Pulling.3. Keeping the guy from moving around.Grabbing the sleeve reinforces the control of the uke.
As Philip Smith pointed out after the grab on the sode [sleeve] has been applied to your partner a sharp tsuki to the face/lower maegeri to the kneecap etc/ or a shomenuchi attack can be applied.This type of attack is difficult to deal with especially using shiho nage as demonstrated by Chiba Sensei.
Being grabbed and pushed or pulled can have an adverse effect on a persons stability [both physically and mentally ].any one who is a bit timid try wrestling with some angry 17 stone judoka.From personal experience of this in the past I found it quite thrilling.
By the way the rugged chaps in Glasgow usually grabbed you by both lapels then quietly administered the redoubtable Glasgow Kiss ie a well placed head butt.This was a fairly well known strategy used by tearaways in the period when I was in short pants. Cheers, Joe,