So tenkan movements (as many as I can remember this early in the morning) do not require atemi, and atemi would be superfluous.
I'm not so sure about this...some techniques from the yoshinkan syllibus that are # 2 and do have atemi:
suigetsutsuki taihenko sokomen iriminage
body thrust, body change, side step-in throw
Aihamne, uke strikes to solar plexus, shite pivots and blocks using gaiwan block, trapping the arm with non-blocking hand, after pivoting strikes with elbow atemi to chest or face, shuffle step in body change for throw.
yokomenuchi shihonage osae ni
side strike, all direction throw, pin #2
gyuakuhamne, uke side strikes to shite's temple, shite shuffles to enter and block with same side hand while delivering atemi to the spot between uke's upper lip and nose, then cuts down on uke's striking hand and pivots and body changes for shihonage pin.
Note that in both of these techniques it is appropriate to enter before pivoting
. I'm given to understand that most times people do enter before pivoting...and it is during this phase that atemi is often used. I get this not just from the yoshinkan, but from other styles (aikikai systems) as well.
I also think that atemi may
sometimes be used to cover weak technique. That is one reason I like cross-training in styles that focus on obtaining kuzushi without the use of atemi. It would seem being able to use the atemi would be a part of good basics, and that as someone advances, they might need it less and less to unbalance someone.