Jcastle.info aims to be the most comprehensive guide to Japanese castles available in English. You can start by viewing profiles of the castles below. Login to record your castle visits or write pages of your own.
I'm in the middle of rebuilding the Jcastle.info site due to some problems with my old server. Here is the schedule of milestones. Most of the functional work is done, it's mainly cleaning things up and making a newer better design.