Well, if I were to write down somethings now it would be all incomplete and very crude, so what I'll do for now is only placing some good links and be willing to answer any question about the topic.
Links:
http://shell.world-net.co.nz/~jimgould/index.html (in this site it shows the hand positions for meditation as called "kuji in" but I heard from more than one source and talked to a ninjutsu instructor and they all say it is called "kuji kiri" and in this site "kuji kiri" is that magic spell)