In 1335, the Shiina clan built Uozu Castle as an auxiliary stronghold supporting Matsukura Castle. By 1570, it had fallen under the control of the Uesugi clan, rapidly emerging as a strategic fortress in Etchū Province. For many years, Kawada Nagataka served as its commander.
Following the death of the renowned daimyo Uesugi Kenshin in 1578, his domain plunged into a prolonged civil conflict known as the Otate no Ran. Seizing the opportunity, Oda Nobunaga dispatched his top generals—Shibata Katsuie and Sassa Narimasa—from the Hokuriku region toward Etchū’s borders.
By 1581, Oda’s forces captured Toyama Castle and advanced into Etchū. Katsuie and Narimasa systematically expelled both Uesugi’s retainers and remaining Ikkō-ikki forces. Realizing the severity of the threat, Uesugi Kagekatsu (1556–1623), Kenshin’s heir, hurriedly reinforced Uozu Castle with trusted vassals.
By March 1582, combined Oda armies under Shibata, Sassa, Maeda Toshiie, and Sakuma Morimasa had attacked both Matsukura and Uozu. Approximately 10,000 besiegers confronted around 4,000 defenders at Uozu.
Unlike the mountain-stronghold of Matsukura, Uozu was a flatland castle (hirajō) near Toyama Bay, featuring two defensive lines: the central hommaru and an outer ninomaru. The hommaru was a near-square enclosure surrounded by a water moat with a single bridge at the entrance. The ninomaru corked around three sides in a “U” shape and also had its own moat. The castle lacked stone walls, yagura towers, or a donjon—instead, it relied on earthen ramparts (dorui) topped with clay walls (dobei), and watchtowers at each corner of the hommaru.
When Oda’s army appeared, the castle’s commanders sent an urgent plea to Kagekatsu. However, internal Uesugi strife, betrayal by Shibata Shigeie, and threats in Kaga and Shinano caused a delay. Meanwhile, Oda’s forces wore down the defenders with constant assaults.
In early May, Kagekatsu himself departed from Kasugayama Castle, captured the strategic Tenjin Hill, but failed to break the siege. Upon hearing news of a possible attack on Kasugayama, he withdrew. Left unsupported and starved of supplies, the Uozu garrison rapidly deteriorated.
After nearly three months of siege, in early June, thirteen senior Uesugi commanders chose to commit seppuku rather than surrender, and Uozu Castle fell. Oda’s forces had planned to advance into Echigo, but news of Nobunaga’s death in the Honnō-ji Incident sparked panic. Many commanders ordered a retreat from Etchū, and Uozu returned to Uesugi control without further fighting.
See also
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The Second Siege of Jinju Castle
During the two Korean campaigns of the 16th century, the Japanese repeatedly had to capture enemy fortresses and defend occupied or constructed fortifications from the combined Korean and Chinese forces. Among all the operations of that time, the second siege of Jinju Castle is considered the most interesting from the point of view of siege warfare.
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The Siege of Takamatsu Castle
The siege of Takamatsu Castle in Bitchu Province is considered the first mizuzeme, or “water siege,” in Japanese history. Until then, such an original tactic had never been used.
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The Third Siege of Takatenjin Castle
The history of the castle prior to the conflict between the Tokugawa and Takeda clans is rather unclear. According to one version, the castle was built in 1416, when Imagawa Sadayoshi (1325–1420) was governor of Suruga Province and half of Totomi Province. Allegedly, it was he who ordered Imagawa Norimasa (1364–1433) to build this fortification. However, no reliable evidence has been found to support this. Another version is considered more plausible, according to which the castle was built during the conquest of Totomi Province at the end of the 15th century by Imagawa Ujitsuna (1473–1526) and his general Ise Shinkuro (Hojo Soon). In this case, another of Ujitsuna's generals, Kusima Masashige (1492–1521), is considered responsible for the construction.
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Battle of Mimigawa
In 1556, the Shimazu clan launched a campaign aimed at systematically conquering the island of Kyushu. In the same year, the province of Osumi was annexed and a war began with the Ito clan for control of the province of Hyuga. In 1577, Ito Yoshisuke was defeated and fled north, where he sought help from Otomo Sorin, the Christian daimyo of Bungo Province.
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The Siege of Kozuki Castle
The battle for Kozuki Castle was a consequence of Oda Nobunaga's expansion in the Chugoku region. Toyotomi Hideyoshi was appointed to lead the campaign, which aimed to weaken the influence of the Mori clan in these lands. Under his command were famous samurai: Kuroda Kanbei, Takenaka Shigeharu, and Hachisuka Koroku. Amago Katsuhisa, who cherished the hope of one day restoring the Amago clan's lost dominance in western Japan, also joined Oda's army.
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The Siege of Nagashino Castle
Despite his reputation as a failure, created by 20th-century popular culture, especially cinema, Takeda Katsuyori (1546–1582) was in fact a brave warrior and talented commander. However, he always remained in the shadow of his great father, the legendary Takeda Shingen. After Shingen's death, Katsuyori sought to at least equal him, if not surpass him. Therefore, his actions were not always determined by pragmatic calculation. This character trait greatly influenced the subsequent events that led to the demise of the Takeda clan.
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Siege of Nagashima Fortifications
The Buddhist peasant movement Ikko-Ikki, which emerged in the 15th century, had grown considerably stronger and larger by the middle of the following century. It had effectively turned into a large feudal army used for territorial conquests. The Ikko-ikki fought fiercely not only against other branches of Buddhism, but also against the provincial daimyo and the central government.
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The Second Battle of Konodai
Hojo Ujiasu (1515–1571), one of the greatest representatives of the Hojo clan, spent almost his entire life at war. His possessions were in a difficult position: they were surrounded on all sides by aggressive neighbors ready to attack at any moment. In implementing his plans to expand the Hojo clan's influence in the Kanto region, Ujiasu was forced to confront well-known and powerful opponents—the Uesugi and Takeda clans. In the east, his main rival was the Satomi clan.
