Komine Castle is located on a long and narrow hill extending 500 meters from east to west, located on a bend of the Abukuma River, which forms part of the natural defenses of the site. The Shirakawa area and the Abukuma River is the on the main route between the Kantō region and northern Japan, the Ōshū Kaidō, and control of this area was of great strategic importance. The ancient Shirakawa Barrier was once located nearby. The inner bailey is at end of this hill separated into two layers of enclosures, protected by tall stone walls. At the northeastern corner, was a three-story yagura which substituted for a true tenshu. Along the north and west lines were huge earthen ramparts using portions of the original terrain. South of the inner bailey, protected by a wide water moat, was a secondary enclosure approximately 200 x 100 meters which contained the residence of the lord. There were a number of enclosures outside this core area, forming secondary fortifications. The east side of the castle was further protected by outer barrier.
History
Early history
The construction of Komine Castle began in 1340 by Yūki Chikatomo, is a small hilltop fortification with earthen palisades. After the fall of the Satake clan in 1589, the Yūki allied with the Date clan to the north, but were dispossessed in 1590 by Toyotomi Hideyoshi. The Yūki survived as retainers to the Date, and their territory became part of the holdings of Aizu Domain under the Gamō clan. Under the Gamō, Shirakawa Castle was modernized with stone walls. The castle was held by the Gamo until 1627.
Edo period
After the establishment of the Tokugawa shogunate, Niwa Nagashige was transferred from Tanagura Domain to become daimyō of the newly created 100,000 koku Shirakawa Domain in 1627 and completely rebuilt and expanded Komine Castle between 1628 and 1632. During the remainder of the Edo period, the castle passed through the hands of seven daimyō clans with a total of 21 daimyō before reverting to direct control of the Tokugawa shogunate in 1866, on the eve of the Boshin War. During this period the most famous ruler of Shirakawa was Matsudaira Sadanobu.
During the Boshin War, Shirakawa was a stronghold of the pro-Tokugawa Ōuetsu Reppan Dōmei and came under attack during the Battle of Aizu by the pro-imperial army of the Satchō Alliance. Although the invading army was outnumbered, it had superior artillery, and Komine Castle had been designed primarily to defend against attacks from the north, so its southern approached were more lightly fortified. The castle fell to the Meiji government on May 1, 1868. Many of the structures of the castle were destroyed during the battle, and much of what remained, including a large section of its stone walls, were later pulled down following the abolition of the han system. The site was transformed into a public park. In 1991, a three-story tenshu was reconstructed on the foundations of the original tenshu, and in 1994 one of the gates was restored. These structures suffered significant damage during the 2011 Tōhoku earthquake.
