First, just let me say, coolest stamp EVER - thank you so much to conejo. So! This is Inuyama Castle, one of only twelve castles still standing in Japan predating the Edo period and sometimes said to be the oldest castle in Japan, period. Construction was completed in 1440. It has changed hands many times throughout its long history, and it is the only castle to ever be privately owned and still have national treasure status. It overlooks the Kiso River.