Re: Identification of Aikido forms in other martial art system?
Aikido really doesn't have any original waza. Anything you might see that "looks effective" in and of itself, particularly, has been done before in other systems.
What is interesting if you look at older jujutsu systems and such from the perspective of Aikido's basic waza is that you might be looking at three or four techniques in the other system, that a practitioner of that system might not regard as being the same thing, but in Aikido they are all slight variations of ikkyo, for example, or kotegaeshi.
Kotegaeshi in particular is absolutely omnipresent across multiple cultures and systems. It seems like as soon as we learned to chisel stones to have a sharp edge, we learned to take the slack out of that hand, move to where the other hand can't hit us, and break the arm or throw the person.
I can't dig up a citation right now but I think the idea that the founder of Hapkido trained with Takeda has been pretty much shown to be false.