The Site of Takamatsu Castle preserves the memory of one of Japan's best-known siege stories: Toyotomi Hideyoshi's flooding of the castle during the campaigns of the late 16th century. Little of the original stronghold remains, so the visit is more about imagination and historical context than walls and towers.
It is worthwhile for travelers who enjoy samurai-era history and are already exploring the Kibiji plain around Okayama. Read up before you go, because the landscape is quiet now; the drama lies in understanding how water, engineering, and negotiation decided the fate of a castle.