Being an old Ki Society guy, I thought that would be obvious to you. In my recollection, there was a happo undo drill in Shin Shin Toitsu Aikido. The eight directions are all on the horizontal plane and they rotate around as in a compass 45 degrees apart. The undo can be done with bokken as in happo giri or without weapons as in happo ikkyo.
I wasn't even thinking in direction (see what I did there
)!. I was thinking it some derivation of six directions as was being mentioned and not THAT eight directions. Apart from the undo that we do before every class we most commonly do it as the eight move jo kata.