Web browsing the aunkai website and noticed this:
It seemed noteworthy to me because many of the body positions seem to me to be strikingly similar (though by no means the same) as those contained within Ueshiba's daily practice called the rites of spring as preserved by Hikitsuchi Sensei.
In order from left to right on the Aunkai page, the first is definitely part of the rites of spring, the distinction being that the knees are not bent in the rites of spring. The second I'm not so sure but moving into the first position in the rites of spring certainly proceeds through this posture though it is not held for long (though I suppose it could be). The third on the aunkai page looks to be a framework you need to work on to develop the rowing exercise properly. The fourth on the aunkai page I don't beleive is part of the rites of spring and looks more like a Tai Chi exercise to me.
I find them particularly interesting because though similar, they are definitely not the same but I'd wager they contain many of the same principles or perhaps slightly different ones more suited to what Ueshiba wished aikido to be as opposed to the aims of the Aunkai. Also because Hikitsuchi was one of Ueshiba's only 10th Dans, awarded before Tohei and certified too unlike others verbally awarded.
Also, Ueshiba apparently practised these exercises daily or similar exercises at any rate in combination with breathing exercises and kotodama. They are also the sort of exercises that can easily be ignored as mystical nonsense of the kind frequently spouted by the founder or so we're told.
Additionally, many fragments of the rites of spring have found their way into various warmup exercises used by various students of Ueshiba, leading us back to the idea of hiden in plain sight again.
Anyway, some food for thought. If anyone has any more info or thoughts please share.