Castles are not a European exclusive.
Eric O. (self described corporate librarian) in Tokyo has been on a mission to share everything we should know about Japanese Castles on J Castle (in English) since 1999.
According to Wikipedia Japanese Castle pages , Himeji Castle located in Himeji City, 50 kilometers west of Kobe is most popular.
On castles road for Tokyo Thursdays # 264
Previously:
Unable to Get Print Copy of Japan Beer Times ‘Summer 2013’ Issue, Download Craft Beer Japan App
(* Photo of Himeji Castle by 663highland -February 2006-via Wikipedia)