My friend said that he found it on the wall of one of the very few bunkers that wasn't blown up with satchel charges, hand grenades, artillery or burned out with flame throwers. He said that there weren't too many of those since the Marines had a very strong compulsion to shoot first and often.
Hi Nancy, From what I remember of Japanese, I can say it's an old style kanji. A lot of the younger Japanese generations can't read that anymore. Your best bet would be a post on craigslist.