The pamphlet tells me this is a "castle" — but the structure in front of me defies that description. Granted, my frame of reference is greatly informed by the impressive edifices of Kumamoto, Himeji and Matsumoto that date back to the gory Sengoku (Warring States) Period spanning some 150 years from the mid-15th century before the country was unified under the Tokugawa Shogunate.

Such imposing turreted buildings dotting the Japanese archipelago are what most visitors — and natives alike — flock to see. Yet here in Kikuchi, a small town in northern Kumamoto Prefecture, a castle that predates all of those other bastions dominates the hilly landscape.

While today's Kikuchi is, admittedly, a backwater in Kyushu, in the seventh century it played a crucial role in the defense of the Yamato state against a possible Korean invasion. In 663, after a force sent to Korea to assist the friendly province of Baekje was defeated by Chinese-backed armies, the real possibility loomed of Japan being invaded.