Ron Ragusa wrote:
Not all tenkan is done just to match uke's body direction. There are numerous techniques that use tenkan as part of the take down or projection of uke during the application of the technique. The tight circular motion executed by nage forces part of uke's body to assume a path with a greater radius; the part of uke's body being held by nage will travel a path more in line with nage's vector. Uke is therefore forced to reconcile the conflict where his single body must assume more than one vector and velocity simultaneously. Since acceleration is a function of velocity and direction, uke's body is accelerated at different rates all at once. The result is he is taken off balance and thrown.
Y'know... all you've got to say is that I'm wrong about using "tenkan" for instance with Sayu Nage and try to support it. Right now, looking at your statement above, it appears that the best you can come up with is that Tenkan is "part of" a number of throws. It's "part of" some forms of Sayu Nage and other throws and it does not necessarily involve what some people are calling "centrifugal force". "Tenkan" means "turn"... it doesn't mean "application of centrifugal force". Actually, I'm a little stunned that this could come up. No wonder some people don't want to define Aikido.