Who says there's no atemi in Aikido?
As I watch this video, I recall images of Pierre Chassang explaining, as I do today, the importance of the rotation of the body's axis:
To capture the imagination, Pierre talked about the shoulder punch.
He wasn't wrong; when the rotation is violent in kata dori, it is transmitted to uke's whole body through his grip, and it has a dazzling effect on him.
Everyone knows that ikkyo is a control technique (katame waza) which is obtained by blocking uke's elbow. But to make the point properly, this information should always be given with the following precision: the lock is only put in place in the second part of the movement.
This would avoid the general tendency to act too soon on uke's elbow, in a situation where tori does not have the means to do so, and where uke's body has not been moved into the position where this control becomes feasible.
It is in fact impossible to act on uke's elbow before the rotation of the body gets underway: it is the rotation of the body that places uke's arm (and body) in such a position that the arm-lock then becomes possible. Hitting the throttle before starting the engine has no effect on the car.