In Japan, you occasionally hear some Aikido teachers say tai no tenkan instead of tai no henka.
It is the contraction of two expressions: tai no henka on the one hand and irimi-tenkan on the other (tai no henka + irimi tenkan = tai no tenkan).
Tai no henka is the basic movement in Aikido, but nevertheless it is still a movement, and like all Aikido movements, it obeys the principle of Aikido action, which is irimi-tenkan. Irimi-tenkan is the root and driving force of tai no henka.
The first movement of irimi-tenkan is irimi (to enter), the second is tenkan (to turn). The second step of tai no henka is therefore obviously a tenkan. The homophonic proximity between henka and tenkan makes it quite natural for a Japanese speaker to say tai no tenkan instead of tai no henka. This approach, which may not always be conscious, is a way of expressing, that tai no henka has irimi-tenkan as its core.
The video shows how the irimi-tenkan principle is intrinsically linked to the tai no henka movement:
Tai no henka is the most basic movement to illustrate the irimi-tenkan principle, and that is why O Sensei required it to be practised at the beginning of each training session. But in truth, every Aikido movement is tai no henka in the sense that it reproduces the same change (henka) in the position of the body (tai) to move the latter - by means of irimi-tenkan - from a dangerous position to a safe position. The technique appears as a consequence of this movement. Just as irimi-tenkan is found in tai no henka, tai no henka is found in every Aikido technique.
