Thanks for the answers so far.
It is not that I don't know how to do nikkyo (as far as you can...
) but is gave me some thought of how to explain to my own students the difference between ikkyo and nikkyo. For example: gyuaku hanmi ikkyo and nikkyo omote are the same way preformed exept for the pin at the final stage where with ikkyo the arm is horizontal on the tatami and with nikkyo the arm is vertikal. That is why I asked your opinon about what for you the nikkyo pin is. (or perhaps better, where is it in the technique for you)
Not that I change the way I have learned it but just to discuss it.
Perhaps it is a language thing......