It seems that notation software for the shamisen is sort of a grail quest, so I'd love to hear how you notate your shamisen scores – pencil and paper, graphical cut and paste of some sort, or whatever. There are many really nice examples of printable scores all over the web …
And if you use some graphical software, where do you get the specialized symbols katakana (?) and others.
I have a Mac, so something that works on that box would be nice.
So, I finally figured out how to do it. It was not intuitive at all. There isn't much about that program that works the way you might expect. The workflow is clunky and I bet it would take forever to transcribe even a short piece of music. :/