The American School In Japan is the high school these papers were found at. It's basically an English speaking school in Japan I guess....right...someone is selling the 1997-1998 yearbook on ebay!
http://cgi.ebay.com/THE-AMERICAN-SCH...2#ht_500wt_956
Utada's picture would be there...and possibly a signature? I wish I could buy stuff from ebay =[