The siege of Otsu Castle was part of the Sekigahara campaign, during which the so-called Eastern Coalition, led by Tokugawa Ieyasu, fought against the Western Coalition, led by Ishida Mitsunari. Otsu Castle was built in 1586 by order of Toyotomi Hideyoshi near the capital Kyoto, on the site of the dismantled Sakamoto Castle. It belonged to the type of “water castles” — mizujō — as one side of it faced Japan's largest lake, Lake Biwa, and it was surrounded by a system of moats filled with lake water, which made the fortress resemble an island.
The layout of the castle and its strategic importance
The castle's layout included three courtyards, extending from the lake to the mainland. These courtyards were separated by moats and protected by stone walls, with the walls of the inner courtyards being higher than the outer ones, which allowed the enemy advancing from the mainland to be fired upon from all levels of the fortifications. The outer courtyard was connected to the mainland by four bridges, and it was believed that the castle was almost impregnable from the land side — it could only be taken from the lake.
By 1600, the commander of Otsu was Kyogoku Takatsugu. This commander had previously served Toyotomi Hideyoshi, but in the Sekigahara campaign he joined the side of Tokugawa Ieyasu. The garrison of the fortress numbered about three thousand soldiers. The castle was located in a strategically important place — it controlled the roads along Lake Biwa, as well as one of the routes leading to Kyoto.
The beginning of the siege
Ishida Mitsunari understood the importance of this hub and believed that the capture of Otsu would be an important stage in the entire campaign. He assigned a 15,000-strong army under the command of four of his generals to the siege. On October 13, the forces of the Western Coalition approached the fortress. Before their arrival, the garrison under the command of Takatsugu burned down the outer town so that the enemy could not use the buildings as cover.
The troops of Mori Motoyasu, Tatibana Muneshige, and Tsukushi Hirokado took up positions on the land side, while Masita Nagamori's fleet blocked the fortress from the lake side. Mori Motoyasu attacked the main castle bridge leading to the entrance of Miideraguchi with a force of 11,500 soldiers. At the same time, 2,500 of Tsukushi Hirokado's warriors stormed the bridge leading to the entrance of Kyōmatiguchi, while Tachibana Muneshige attacked the secondary bridge of Hamamiguchi with a thousand soldiers. The remaining troops blocked all approaches to the castle.
Despite their numerical superiority, the rapid assault was unsuccessful. After several unsuccessful attacks, the generals of the Western Coalition switched to a blockade tactic, combining constant shelling of the defenders with periodic attacks on different sections of the defenses.
“The siege as a spectacle”
According to some sources, the locals perceived the siege as a real spectacle. Numerous spectators gathered on the slopes of the nearby mountains, coming even from Kyoto. People brought food and sake with them, settled in comfortable places, and watched the samurai fight and die under the castle walls.
Shinobi sabotage and an unexpected effect
On the sixth day of the siege, Takatsugu sent a group of shinobi (ninja) to the enemy camp, who managed to steal several banners of the Mori clan. The next morning, these flags were hung on the castle walls. The commandant probably hoped to demoralize the enemy—such psychological warfare tactics had been used before, for example, during the siege of Hataya Castle. However, this time the result was the opposite.
Seeing his clan's flags on the walls of Otsu, Tatibana Muneshige decided that his allies from the Mori army had already taken control of their section of the fortifications. In order not to fall behind, he immediately launched his warriors into a new fierce attack. Muneshige's samurai stormed the castle continuously, day and night, and artillery was brought in to destroy the gates and walls.
Seeing Muneshige's activity, the other commanders also intensified their attack, and by the next day, the besiegers had captured the outer ring of defenses. Now the real victory flags of the Mori clan were flying on the walls.
Surrender and consequences
On October 21, 1600, Kyogoku Takatsugu, realizing the futility of further resistance, admitted defeat and surrendered the castle. On the same day, however, a key event in the entire campaign took place — the Battle of Sekigahara, in which Tokugawa Ieyasu won a decisive victory over the Western Coalition.
Although the Otsu garrison was almost completely destroyed, Takatsugu's stubborn defense was of strategic importance—he held back the enemy's 15,000-strong army and prevented it from taking part in the general battle, thereby helping Ieyasu achieve success.
The fate of the commandant
After the surrender, the generals of the Western Coalition allowed Kyogoku Takatsugu to shave his head and retire to a monastery on Mount Koya. Later, when Tokugawa Ieyasu's victory became indisputable, Takatsugu was rewarded for his contribution to the campaign with an estate in Wakasa Province. Thus ended the siege of Otsu, one of the episodes that influenced the outcome of the great battle of Sekigahara.
See also
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The Siege of Shiroishi Castle
The siege of Shiroishi Castle was part of the Sekigahara campaign and took place several months before the decisive battle of Sekigahara. The daimyo of Aizu Province, Uesugi Kagekatsu, posed a serious threat to Tokugawa Ieyasu's plans to defeat the Western Coalition, and Ieyasu decided to curb his actions with the help of his northern vassals. To this end, he ordered Date Masamune to invade the province of Aizu and capture Shiroishi Castle.
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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
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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
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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
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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.
