I think to help me forge this paper, I would ask if anyone has any information about when the name change of Ikkajo to Ikkyo occurred and who did it. Like i say it seems likely to me that if Shioda called it Nikajo he learned to call it that from O-Sensei. Also but at some point the aikikai started using the term ikkyo. Was it Doshu Kisshomaru Ueshiba? I dont find this likely.
Here's a thread from a couple of years ago on this same question: http://www.aikiweb.com/forums/showthread.php?t=13842
Read Peter Goldsbury's post #13, in which he explains what kajou
means, and also states in passing that it was Kisshomaru Ueshiba who changed the counter to kyou
I wonder if older students might use the terms kajou
interchangeably just as older martial artists might use jujutsu
interchangeably, tending toward one or the other simply as personal preference.