Greg Jennings wrote:
I got those terms directly from Hans Goto Sensei and from Saito Sensei's original series, "Traditional Aikido".
Kotai = "Rigid Body"
Jutai = "Supple Body"
Ryutai = "Flowing Body"
Kitai = "Energy Body" S.K.A. "Takemusu Aiki"
We usually speak more broadly in terms of "Kihon" (basics) and "Ki-no-nagare" (Energy Flow).
It's one pedagogical method. It seems to work for me.
As a footnote to my earlier post, the translation for 固体稽古 is 'solid exercise' (as per Bill Witt's translation of "Traditional Aikido"). If you were to follow the assumptions in the above post, the compound word 'ko-tai-gei-ko' would mean 'solid body respect old', which is nonsense.
Kotai means solid, as opposed to liquid. Thus 'kotai renryo' means 'solid fuel', but 'rigid body' seems far too literal.
I have no problem with the type of training you are thinking of, only with Mr Goto's translation.