"Originally called Ozakajo, it is one of Japan's most famous castles, and played a major role in the unification of Japan during the sixteenth century of the Azuchi-Momoyama period..."
"Osaka Castle." Wikipedia, The Free Encyclopedia. 13 Apr 2008, 15:34 UTC. Wikimedia Foundation, Inc. 1 May 2008 <http://en.wikipedia.org/w/index.php?title=Osaka_Castle&oldid=205342295>.