It is common in Jujutsu to attempt to disarm an opponent by somehow grabbing part of their weapon and levering it against the little finger edge of the wrist - in the configuration of what we call 'side wrist crush' (yokotekubihishigi).
There is always some discussion as to the correct placement of the left hand on the katana in terms of how high it is on the handle. Note here the grip of the Katori style - the bottom of the handle is far enough into the palm to allow it to be released and rotated forward so the palm presses on the end of the handle, avoiding being trapped in a side wrist lock position and allowing a solid thrust. In the Katori style the hands are very much alive on the handle.
There is always some discussion as to the correct placement of the left hand on the katana in terms of how high it is on the handle. Note here the grip of the Katori style - the bottom of the handle is far enough into the palm to allow it to be released and rotated forward so the palm presses on the end of the handle, avoiding being trapped in a side wrist lock position and allowing a solid thrust. In the Katori style the hands are very much alive on the handle.
This image shows when the handle has been rotated in the palm as it has been twisted up - the sword can be pushed from this position. This manoeuvrability comes from the style of bottom hand grip used.
To quote one translation of Musashi's work: "Generally, I dislike fixedness in both long swords and hands. Fixedness means a dead hand. Pliability is a living hand. You must bear this in mind."