Glad I understand at least the basic level. I suppose more advanced level is about correct dosage.
Some shihan display a kind of impulse like technique and in that exact moment take the balance and execute a technique. I suspect this eventually everything you can see 'at the outside'.
With someone like Saotome Sensei, uke's balance is already gone by the time he actually touches nage. Which of course makes technique very easy.
It's possible to accomplish that without "internal" skills of any kind, through timing, body movement, etc. But it becomes more difficult the more skillful the attacker is.