cconstantine

I have no direct knowledge of O'Sensei's grip. But I can certainly vouch for being the recipient of "crushing" grips that were not based solely on raw muscle power, and for very muscular-strong grips that had little control, and no "crushing" affect.

It seems patently obvious that it also matters how one grips. The exact nuances of placement, orientation, position are aspects of a grip which one does automatically after much practice. I believe O'Sensei had great physical strength, and combined with exceptional placement, extension during the grip, connection, etc a "simple" (simple in the eyes of someone not familiar) grip would certainly be "crushing" to the recipient.