While I respect Boon and his opinion, I have to disagree a bit.
I do think this is an important waza IF you are looking for the power that lies at the heart of aikido. Just my opinion, but I think that while aikido without this power can be very interesting, it's usefullness is seriously diminished without that power.
This waza without proper kokyu is low percentage. With proper kokyu? In a true fighting context? I don't know enough to say yet.
By the way...I have felt this waza applied to me by a ryoku dan from Yamaguchi Sensei's lineage. It can be made to work on me anyway. Dramatically, I might add...
He he he Ron....
Speaking of power... I learn about power generation from the doing the Kihon Dosa exercise. I learn about generating power from doing the suwari waza version of kihon waza.
I meant to say... in the Yoshinkan syllabus, there are plenty of more directly useful techniques to play with. Spending an insane amout of time to perfect such a low percentage technique is a poor Return of Investment ratio.... but to each his own.
Just some trivia... yesterday we were doing katate aya mochi ikkajo ichi. Some uke commented that my irimi is very strong but it is not off the muscular nature, I can only attribute it to proper kokyu power generation. I am please as punch for the time being.