
Matsushiro Castle, originally known as Kaizu Castle, is located in what was once Matsushiro town, now part of Nagano City. The site is recognized as a National Historic Site of Japan. Situated on the northern Shinano flatlands between the Chikuma River and a former riverbed that serves as a natural outer moat to the north, the castle and its surrounding town were prone to flooding due to their location.
The castle was designed in a concentric layout, with the Central Bailey (Hon-Maru) at its core, protected by walls and initially featuring a tenshu (main keep) in its northwest corner, which was later replaced by a yagura (turret). A moat surrounded the Central Bailey, which was itself encircled by the Second Bailey (Ni-no-Maru), featuring earthen ramparts and stone fortifications near its gates. The Second Bailey was bordered by a dry moat on its south and east, while the Third Bailey (San-no-Maru) lay beyond. The palace and official residences of the daimyo were located in the Hana-no-Maru enclosure, adjacent to the main defenses.

The castle’s origins date back to 1560, when it was built by Yamamoto Kansuke under the command of Takeda Shingen and named Kaizu Castle. Kosaka Danjo (Kosaka Masanobu), a retainer of the Takeda clan, was its first commander. Takeda Shingen used the castle in his battles against Uesugi Kenshin for control over northern Shinano Province. The castle is located near the site of the famed Battle of Kawanakajima, where the Takeda and Uesugi forces fought several times.
After the fall of the Takeda clan, the castle changed hands, eventually coming under Oda Nobunaga's control. However, following Nobunaga's assassination during the 1582 Honno-ji incident, Uesugi Kagekatsu reclaimed northern Shinano. The castle became a point of contention between the Uesugi and Sanada clans. Under Toyotomi Hideyoshi’s rule, the Uesugi were moved to Aizu, and after Hideyoshi’s death, the Tokugawa shogunate assigned Sanada Nobuyuki to Matsushiro Domain in 1622, relocating him from Ueda.
The castle was renamed Matsushiro Castle in 1711 by Sanada Yukimichi, the third-generation daimyo of the Sanada family. After a fire destroyed the castle in 1717, it was rebuilt the following year with the help of a 10,000 ryo donation from the Tokugawa shogunate. The castle sustained severe damage from a flood in 1742, and reconstruction continued until 1758. In 1770, the palace structures were moved to the Hana-no-Maru enclosure and rebuilt in 1804, but much of the castle was damaged again by an earthquake in 1847. Following another fire in 1853, the palace was rebuilt, and a secondary palace was constructed outside the castle in 1864.
After the Meiji Restoration and the abolition of the han system, most of the remaining structures of Matsushiro Castle were dismantled in 1871. In 1873, the remaining parts were destroyed by a fire, leaving only the stone foundations that remain today.
See also
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Kaminoyama Castle

Kamino-yama Castle stood at the center of an important logistics hub, in the middle of the Yonezawa Plain, which served as the gateway to the western part of the Tohoku region. Roads connecting the Aizu, Fukushima, and Yamagata areas intersected here.
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Imabari Castle

Tōdō Takatora (1556–1630) served at different times as a vassal of several famous clans—Azai, Oda, Toyotomi, and Tokugawa. He took part in the Battle of Anegawa (1570), the Battle of Shizugatake (1583), the invasions of Kyushu and Korea, the Sekigahara campaign (1600), and the Siege of Osaka (1614–1615).
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Iwakuni Castle

Kikkawa Hiroie (1561–1625) was the grandson of the famous daimyo Mori Motonari and a vassal of the Mori clan. Under Mori Terumoto, he fought in both Korean campaigns and took part in the defense of Ulsan Castle. During the Battle of Sekigahara, Hiroie stood with his 3,000-man force on the side of the Western Coalition; however, even before the battle began, he sent Tokugawa Ieyasu a secret message stating that he did not intend to fight Tokugawa’s troops. As a result of his inaction, 15,000 soldiers under Mori Hidemoto were also unable to enter the battle, since Hiroie blocked their path.
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Gujo Hachiman Castle

Gujo Hachiman Castle is located on 350-meter Mount Hachiman, near the confluence of the Yoshidagawa and Kodaragava rivers, and not far from the Nagaragawa River. During the Sengoku period, this area was of great strategic importance: it stood at a key crossroads of routes connecting Mino Province in the south with the Sea of Japan in the north, and Hida Province in the east with Echizen Province in the west.
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Amagasaki Castle

The founding year of Amagasaki Castle is traditionally considered to be 1617, when Toda Ujikané built his castle here, making it the administrative center of the Amagasaki Domain. However, as early as the Sengoku period, a fortress built by the Hosokawa clan already stood on this site. After the fall of Itami Castle in 1579, Araki Murashige—formerly a vassal of Oda Nobunaga who had rebelled against him—fled to this earlier castle.
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Hiroshima Castle

Mōri Terumoto (1553–1625) was the grandson and rightful heir of the renowned Mōri Motonari. When Terumoto became the head of the Mōri clan in 1571, he inherited vast territories covering a large part of the San’in and San’yō regions in western Honshū. In addition, the Mōri clan possessed the largest and most technologically advanced naval fleet of its time.
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Fukuyama Castle

After the defeat of Toyotomi Hideyori’s supporters in the Osaka Campaigns of 1614–1615, many clans in Japan still remained not fully loyal to the Tokugawa shogunate, especially in the western Chūgoku region. Mizuno Katsunari (1564–1651), a cousin of Tokugawa Ieyasu, became the first of the Tokugawa house’s close retainers, the so-called fudai daimyō, to be relocated to this strategically important area.
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Tiba Castle

The founder of the Chiba clan is considered to be Chiba Tsunesige (1083–1180), who in 1126 moved his residence to the Inohana area and built a strongly fortified stronghold there. Although Tsunesige himself came from the Taira clan, the Chiba clan later supported Minamoto no Yoritomo, the future founder of the first shogunate.
