In my opinion, this is how "aiki" is meant to work. It's how I teach it. The way you describe it, there's an almost simultaneous movement. That's unlikely to happen. So, how do we explain teaching that? Well, if you're actually moving, responding to the opponent, and striking, then you will sometimes find yourself properly in motion at the right moment. I see this happen from time to time in boxing: one guy throws a good punch just as the other guy decides to slip to the outside. That's a perfect set-up for aiki-style techniques, and it's not about responding to a single, specific attack (as the classical training seems to suggest), but about working the situation with other tools until the right moment opens up, then taking advantage of it. So, we don't have to be preternaturally fast, have precognition to know what's coming, or any of that. We just have to be able to hold our own and recognize the openings. I don't think a pure-aiki approach can provide that.Now as the old book says same set up (but uke is going to deliver the strike with full intent as in try to cleave ya head in two) as he starts his movement then nage "goes" an by the time he (nage has entered ) the velocity of the strike is not at full force (some if not a large part is still stored in uke) block /deflect apply atemi then go for Ikkyo and use the stored engery of the strike to allow the technique to work fully ...make sense from your aiki background ? and the atemi is not only to break his structure but also to allow the "stored" energy out and for you to use it