Okay, then you're going to have to explain this to me. Here's the situation: Shidachi is in a strong chudan stance; no suki. Uchidachi is a in a strong chudan stance; no suki. The situation is a stalemate. This is "aiki", as in "kisetsu ga au". Per the kata, shidachi drops his strong chudan stance, to invite uchidachi's attack, or any kind of response, and create a suki. This is called "departing from aiki". Breaking the stalemate. This is the use of the term "aiki" in YSR, and the use that Mr. Shishida is talking about.
I'm not saying the body skills now popularly known as aiki did not exist in these old arts. I think they did and do exist; I believe they are in Yagyu Shinkage-ryu. However, I don't believe the use of the term "aiki" above refers to them. I have to side with Mr. Shishida in the idea that the term was used differently at that time, and different terms were used to refer to the body skills. But I am honestly open to persuasion. If you can explain to me how the above situation is directly related to the body structure and skills used in aiki arts, I'll happily revisit my position.
I was not discussing "the breaking of aiki" anywhere. I was quoting or more directly discussing the use of Aiki and what might have created it in the series of examples you offered and with ones I added..
The example you just outlined above I did not discuss.
To discuss that-one can (not necessarily always) break a connection, but depending on what that opponent was doing or intending to do just prior ...then retreating or adopting a different position can be leading/causing/creating an initiative from the opponent, thus maintaining a connection throughout. Two people connecting does not make aiki, it's just two people facing off...anyone can do that. One may have aiki both may not, one may lead and cause one to follow...both can just be ner do wells with weapons in their hands..
Leading the mind in offense/ defense is another aspect of aiki. I am just a bit jaded as to how well that all works outside of a closed system with students. There are aspects I think work in dialogue, de-escalation of violence or anger, on to actual fighting, but I think it is less dramatic than some of the ..er....stuff we typically see in the arts.
In any event I don't think we we disagree much at all..