The 1580 Battle of Omosu (Omosu no Tatakai) was one of many conflicts between the Hojo and Takeda clans during Japan's Sengoku period. What sets this battle apart is its rarity as one of the few naval engagements in pre-modern Japan. The conflict occurred off the coast of the Izu Peninsula, involving the fleets of Hojo Ujimasa, the leader of the Hojo clan, and Takeda Katsuyori, the head of the Takeda clan.
In a covert operation, the Fūma ninja, led by Fūma Kotarō, infiltrated and attacked a Takeda camp during the night. This surprise assault created chaos and confusion among the Takeda forces, leading them to turn on one another, causing significant casualties.
As the naval standoff continued, the land armies of both clans advanced towards each other. Ultimately, the Hojo clan emerged victorious.
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First Battle of Azukizaka
In response to the Oda clan's advance into the western part of Mikawa Province, in August 1542, the combined forces of Imagawa Yoshimoto and Matsudaira Hirotada (father of the future shogun Tokugawa Ieyasu) advanced into the Ikutahara area.
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Battle of Ankokuji
As a result of the summer campaign of 1542, the Suwa clan was completely defeated. Takeda Shingen stationed his military contingent at Uehara Castle. Takeda's army general, Itagaki Nobukata, subsequently became the commandant of this castle.
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The Siege of Matsuyama Castle
In 1537, the head of the Ogigayatsu branch of the Uesugi clan, Uesugi Tomooki, died. He was succeeded by his son, the thirteen-year-old Uesugi Tomosada (1525–1546). Hojo Ujitsuna (1487–1541), who had long been planning to expand his holdings in Musashi Province, decided to take advantage of the new daimyo's inexperience. He assembled an army of 7,000 soldiers and marched on Kawagoe Castle.
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The Siege of Unokuchi Castle
One of the important steps in the career of every Japanese commander was the uijin, the first military campaign in which he took part. For the legendary Takeda Shingen, according to some sources, this campaign was the siege of Unokuchi Castle.
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Battle of Arita-Nakai
By 1517, Takeda Motoshige, lord of Kanyama Castle, was probably the most influential daimyo in Aki Province. Ten years earlier, he had served as a vassal of the Ōuchi clan and participated in Ōuchi Yoshiyuki's campaign in Kyoto. This campaign was part of an effort to support the deposed shogun Ashikaga Yoshitane.
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The Siege of Arai Castle
Hojo Nagauji (Soun) (1432–1519) went down in Japanese history as one of the most notable figures of his time. He is considered a prime example of a gokoku-jo daimyo. The process of gokoku-jo literally means “the lower classes defeat the upper classes” and in Japanese history was expressed, among other things, in the elevation of minor samurai to the status of owners of entire provinces.
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Battle of Sakai
Ōuchi Yoshihiro was an influential shugo of the provinces of Suō and Nagato and played an important role as a supporter of the Ashikaga clan during the war with the Southern Court. His greatest achievement was forcing the Southern Court emperor to surrender in 1392, which brought an end to the Nanboku-chō period. This victory strengthened the Ashikaga clan's position and marked the end of the long-standing rivalry between the two imperial lines.
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Battle of Shijonawate
After Kusunoki Masashige's death in the Battle of Minatogawa, his son, Kusunoki Masatsura, continued his work supporting the Southern Imperial Court in the Nanboku-chō period war. He took on his father's legacy not only as a duty, but also as a way to remain faithful to the ideals for which Masashige had given his life.
