When he was teaching tai no henka, Morihiro Saito would use a little pedagogical trick to show that the movement had to be done without the slightest force.
He would ask uke to hold his wrist with all his strength, and then he would perform the irimi-tenkan rotation, waving the gripped hand gently, to show that uke's grip - however powerful - in no way hindered the movement. The success of this fundamental movement - as of all Aikido movements - does not depend on physical strength, but on the correct use of the rotation.
The video repeats this little teaching trick, the visual aspect of which is more instructive than many explanations:
Any attempt to use physical force in an Aikido movement amounts to measuring yourself against someone else, which is a guarantee of losing. You shouldn't measure yourself against anything or anyone, apart perhaps from the Gods, as O Sensei used to say.
At the end of his demonstration, Saito Sensei would always comment on his little trick with a smile: chikara naï (no strength).
I saw him do this so many times that he is still there in front of my eyes when I tell this anecdote. Men don't die as long as they live in the memory of other men.
