What Are Japanese Castles?
Japan’s towering castle keeps are products of the Warring States period (1467–1600), an era of bloody clashes between regional warlords. Beginning in the 1400s, the ruling Ashikaga clan began to lose control of the increasingly fractured country. Different factions spent the following decades battling to expand their territory, and Japanese castles developed greatly during this long period of near-constant warfare.
The presence of a great keep (tenshukaku) is a distinctive trait of castles from the late Warring States period. Castles of that time functioned as the administrative centers from which warlords controlled their territory. Fortified towns and strongholds had already existed for hundreds of years by that time, but these early “castles” were generally built atop mountains and encircled by earthen embankments or wooden barricades.
Mountaintop castles were easy to defend, but they were necessarily far from farmland and main roads. This made them unsuitable as centers of administration. Beginning in the early 1500s, castles were built on hills rather than mountains, and eventually, they were built on flatland as well. This gradual evolution produced the iconic great keeps for which Japanese castles are now known.
Built in the late sixteenth century, Matsumoto Castle was constructed using a mix of both new and old technology. The successively smaller levels of the Great Keep are similar to those of later castles. However, the architectural structure of the Great Keep, which can be described as one tower stacked onto another, is more indicative of earlier castles. Consequently, Matsumoto Castle represents a transitional phase of castle design.