Re: "Don't use strength!"
Gripping/grabbing and the sensation of muscular strength become fascinating tools to open up different ways of moving.
I find that sensations of muscular strength mean that you can feel a localised source of said strength - for most of us that is things like the shoulders. The converse is where the shoulders are used in a more transparent manner so that you start to feel the whole body, or (heaven forbid!) the tanden... Localised strength has limits which are lower than unified body (even if those limits can be pretty high for some people!).
We have all grown up using localised strength and it takes a lot of retraining and focussed effort to change things.
Purely on the gripping front, it is worth playing with how you grib a bokken - what happens if you use index and second finger for the grip? Is it different if you use your third and little fingers? Check out flexibility while gripping in different ways - how well you can move. Become aware of how the grip affects the rest of the body. Which side of the arm is affected?