Thank you, Rupert and Cady! Very cool!
As for zanshin, I think it was the idea of 360 degrees (omnidirectional/spherical) awareness that caused the association.
...the higher meaning of zanshin, which is a mental aspect maintained before, during, and after an action.
...zanshin is practiced as general awareness of one's surroundings, of which uke is just a small part.
I can see how they wouldn't necessarily be the same things; I'm guessing perhaps zanshin refers more to a mental state than a mind-body state? Being "in the moment" as opposed to being able to absorb and redirect (or whatever) instantly?