wikipedia is always a nice place to start for things like this:
http://en.wikipedia.org/wiki/Japanese_Sign_Languagewhich links to an interesting article:
http://www.deaflibrary.org/jsl.htmlthere isn't any solid info on WHAT the signs are (you might have to get a book on that to find out), but i learned something, that's for sure. definitely not how i would have expected japanese sign language to be like. i pictured maybe something closer to... signing each kana character/syllable, or something.