Iyo Matsuyama Castle

Historically, the center of Iyo Province—corresponding to today’s Ehime Prefecture on the island of Shikoku—was the city of Imabari, while the Matsuyama area was regarded as an agricultural hinterland with broad plains and low hills. During the Muromachi period, the central part of the province was governed by the Kano clan from Yuzuki Castle. With the onset of the Sengoku period, however, this clan lost its former influence and was forced to survive in the shadow of the more powerful Mori and Chōsokabe clans. After Toyotomi Hideyoshi’s forces conquered Shikoku in 1587, the northern part of Iyo Province was granted to Fukushima Masanori, one of the so-called “Seven Spears of Shizugatake.” In 1595, Masanori was transferred to Kiyosu Castle, and the lands around Matsuyama were given to another of the Seven Spears, Katō Yoshiaki, who received Masaki Castle and an income of 60,000 koku of rice.

The Period of Katō Yoshiaki and the Events of Sekigahara

After Toyotomi Hideyoshi’s death in 1598, Katō Yoshiaki pledged loyalty to Tokugawa Ieyasu and supported the Eastern Coalition at the Battle of Sekigahara in 1600. At the same time, the Mori clan—an important ally of the Western Coalition—launched an attack on the Katō clan’s base at Masaki Castle. Despite the small size of the garrison, the defenders managed to hold the castle.

The Founding of Matsuyama Castle

Following Tokugawa Ieyasu’s victory in the Sekigahara campaign, Katō Yoshiaki’s rights to his lands in Iyo were confirmed, and his income was increased to 200,000 koku of rice. In 1602, Yoshiaki received permission from the shogunate to build a new castle, Matsuyama Castle, slightly north of Masaki Castle. It is believed that some parts of Masaki Castle were reused in the construction of the new stronghold. Overall, construction continued for more than twenty-five years.

Layout and Structure of the Castle

The castle was built on Mount Shiroyama, a hill about 100 meters high. Like many hirayamajiro (hilltop–plains castles), Matsuyama consisted of a mountainous section and developed areas at the foot of the hill. At the flat summit was the main enclosure, the honmaru, shaped like a hammer with a handle and measuring roughly 400 meters in length and 100 meters in width. The honmaru was surrounded by high stone walls (ishigaki), and its three entrances were controlled by masugata barbican complexes.

The Tenshuguruwa and the Main Keep

In the northern part of the honmaru stood a separate enclosure known as the tenshuguruwa, designed to protect the main keep, or tenshu. Nearly the entire perimeter of this enclosure was lined with long tamon-yagura turrets or earthen walls (dobei), with yagura towers placed at the corners. This design is characteristic of late castles from the early Edo period and is similar, for example, to the corresponding enclosure at Himeji Castle.

The Second Bailey: Ninomaru

At the foot of the hill lay the relatively small second bailey, the ninomaru. A residence for the castle lord was built here, along with a traditional garden. This area was also well fortified, with defenses that included stone walls about 10 meters high, a water-filled moat, towers, and gates.

Unique Features of the Layout

A distinctive feature of Matsuyama Castle was the presence of vertical stone and earthen walls descending from the mountain section of the castle down to the ninomaru. As a result, the entire slope between the first and second enclosures was incorporated into the castle grounds. Such a layout was extremely rare among other hilltop–plains castles.

The Third Bailey: Sannomaru

Adjoining the second bailey was the third bailey, the sannomaru, which was nearly square in shape and significantly larger, measuring approximately 500 by 500 meters. It was protected by an earthen embankment (dorui) topped with earthen walls (dobei) and a wide water-filled moat (mizubori). Within this enclosure stood the administrative buildings of the Iyo Matsuyama domain, as well as the residences of some samurai.

Change of Lords and Completion of Construction

Katō Yoshiaki did not live to see the completion of the castle; in 1627, he was transferred to the Aizu domain. His successor was Gamo Tadamoto, appointed by the shogunate. Under Tadamoto, the five-story main keep was completed and the ninomaru was fully finished. In 1634, Tadamoto died without an heir, and the castle and domain were transferred to Matsudaira Sadayuki, a member of the Hisamatsu branch of the Matsudaira clan. The Hisamatsu-Matsudaira were classified as shimpan daimyō, close relatives of the shoguns. Under Sadayuki, a new main keep was built in 1642, this time with three stories.

Fire and Reconstruction of the Main Keep

During New Year celebrations in 1784, lightning struck the main keep, completely destroying it by fire. Reconstruction work began in 1820 and was completed in 1854. From that time, the tenshu has survived unchanged to the present day.

The Boshin War and the Preservation of the Castle

The Matsudaira clan held the castle until the beginning of the Meiji period. During the Boshin War in 1868, the daimyō of the Matsuyama domain at the time, Matsudaira Sadaaki (1845–1872), fought on the Tokugawa side. After the imperial forces’ victory, Sadaaki was declared an outlaw. To prevent the destruction of the castle, he chose to submit to the new government, allowed troops from Tosa Province to enter the castle, and withdrew to Jōshinji Temple to repent. His sincerity convinced the emperor; Sadaaki was pardoned, and the castle was spared from confiscation.

Transfer to the City and Restoration Efforts

In 1923, the Matsudaira clan transferred ownership of the castle to the city of Matsuyama. The surviving structures, including the main keep, were designated “National Treasures” in 1935, but lost this status after the enactment of the 1950 law. Restoration of surviving buildings and reconstruction of lost ones began in 1958. By 1986, twenty-nine structures in the main honmaru enclosure had been reconstructed, and in 1992 the gates and a tamon-yagura turret of the second bailey, the ninomaru, were also rebuilt.

The Main Keep and the Museum

The tenshu has survived to the present day in the form of its 1854 reconstruction and is considered the “youngest” main keep among the so-called Authentic Dozen. It is generally believed to be an exact reproduction of the tenshukaku built under Matsudaira Sadayuki and destroyed in 1784. The main keep is designated an Important Cultural Property. Inside, there is a small historical museum displaying armor from the Sengoku period and the Edo period, including sets once belonging to the castle’s commandants.

Other Important Structures of the Castle

In addition to the main keep, twenty other surviving structures within the castle complex are designated Important Cultural Properties. These include the Shichikumon Gate with adjacent sections of walls preserved since the 1854 reconstruction; the Uchibei earthen wall from 1854, notable for featuring all types of loopholes, including mashikuli and ishiotoshimado; the Noharayagura Tower from 1660, one of the few surviving two-story towers in Japan; the Tonashimon Gate from 1635, a rare type of gate without doors; the Ninomonyagura Tower, reconstructed in 1854; the connecting tower of the Kakuremon Gate, preserved since its construction in 1615; and the Ichinomon Gate, reconstructed in 1854.

Current Status

In 2006, Matsuyama Castle was included by the Japan Castle Foundation (Nihon Jōkaku Kyōkai) in the list of the “100 Remarkable Castles of Japan.” The entire castle complex is also designated a National Historic Site.