So, how does it work?
As long as you are able to blend or harmonise with Uke's force/energy/momentum/Ki ("Aiki"), and then effortlessly break his balance & counter ("Ju").
"Aiki" being the "Cause", and "Ju" being the "Effect".
This is what I mean when I say that the secret to achieve "Ju" is through "Aiki".
You may not agree with me, but at least understand what I mean.