The Oda clan came to power in the province of Owari in the 15th century as a result of the so-called gokoku-jo, or “overthrow of the higher by the lower.” By rebelling against their suzerain, the Shiba clan, the Oda were able to achieve independence. However, this victory led to internal strife: the clan split into two rival branches.
One branch, known as Ise-no-Kami, fortified itself in Iwakura Castle. The other branch, Yamato-no-Kami, occupied Kiyosu Castle.
In the middle of the 16th century, a young and energetic commander named Oda Nobunaga rose to prominence in the clan. Making Kiyosu Castle his main base, he began to purposefully unite the entire province of Owari under his rule.
First, Nobunaga brutally dealt with his closest relatives, who were eliminated as dangerous rivals. Then he turned his attention to the neighboring branch of the clan, which held Iwakura Castle. At that time, the castle was commanded by Oda Nobuyasu and Oda Nobukata.
Iwakura Castle was a powerful fortification. It was surrounded by a double moat, stretching approximately 90 meters from west to east and about 170 meters from north to south. The fortress was complemented by watchtowers and other defensive structures.
In June 1559, Nobunaga launched an attack on the castle. First, he ordered the burning of the castle town to clear the approaches to the fortress. After that, the castle was completely surrounded by numerous barricades and was besieged.
The siege lasted more than two months. Nobunaga systematically wore down the defenders, using incendiary arrows, gunfire, and sudden assault attacks.
In the end, the defenders of the castle decided that further resistance was pointless. They opened the gates and surrendered. The garrison was allowed to leave the besieged territory unhindered. After the castle surrendered, Nobunaga ordered the destruction of the Iwakura fortifications and returned to Kiyosu.
During the siege, Yamauchi Moritoyo, the father of Yamauchi Kazutoyo, Nobunaga's future vassal and hero of the battles of Anegawa and Nagashino, was killed. Moritoyo fought on the side of the defeated. The fall of Iwakura Castle marked the final point in the unification of the province of Owari under the rule of Oda Nobunaga.
See also
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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.
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The Fourth Battle of Kawanakajima
The Kawanakajima Plain is located at the confluence of the Saigawa and Tikumagawa rivers in the Japanese Alps. Between 1553 and 1564, five battles took place on this plain between the forces of Uesugi Kenshin and Takeda Shingen.
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Battle of Tonamoto (Nagahama)
At the beginning of the Sengoku Jidai period, the Teshokabe clan was one of the smaller clans in Tosa Province. Its neighbors were constantly at war with each other, engaging in endless skirmishes. Among them, Yosokabe Kunitika stood out as a military strategist of extraordinary talent. It was thanks to these abilities that he managed to defeat the neighboring clans step by step by the middle of the 16th century, expanding the influence of his clan. At that time, the clan's headquarters was Oko Castle.
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The Siege of Katsurayama Castle
The siege of Katsurayama Castle was part of the so-called Third Campaign of Kawanakajima, one of five operations conducted by daimyo Takeda Shingen against the forces of the Uesugi clan in the north of Shinano Province.
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The Battle of Nagaragawa
Saito Toshimasa, later known as Saito Dosan, is considered one of the typical Sengoku daimyo—minor samurai who, in the 16th century, managed to achieve the status of independent princes by the harshest and sometimes unsavory means. His ruthlessness towards his rivals earned him the nickname “Mino no Mamushi” — “the viper of Mino.”
