Hojo Ujimasa (1538 – August 10, 1590) was the fourth leader of the later Hojo clan and the daimyo of Odawara. He continued his father Hojo Ujiyasu's policy of territorial expansion, achieving the largest territorial holdings in the clan's history.
Born in 1538 as the second son of Hojo Ujiyasu, Ujimasa's childhood name was Matsuchiyo-maru. After his elder brother Shinkuro passed away at a young age, Ujimasa became the heir apparent. In 1554, during an alliance formed by Ujiyasu with Takeda Shingen and Imagawa Yoshimoto, Ujimasa married Shingen's daughter, Obai-in.
Around 1559, Ujimasa assumed formal leadership of the family upon Ujiyasu's retirement. The Hojo clan expanded its control significantly under his leadership, including the capture of Iwatsuki Castle in 1560, which brought most of the Musashi Province under their control. Ujimasa participated in several key battles, such as the Battle of Konodai (1564) and the Siege of Odawara (1569).
In 1574, Ujimasa secured the surrender of Sekiyado Castle in Shimosa Province from Yanada Harusuke and gained the allegiance of Yuki Harutomi, a vassal of the Uesugi clan. The following year, Gion Castle in Shimotsuke Province, held by Oyama Hidetsuna, also surrendered. In 1577, Ujimasa invaded Kazusa Province and reconciled with his long-time adversary, Satomi Yoshihiro. This conflict marked the first battle for his heir, Hojo Ujinao.
By 1580, after Takeda Katsuyori's intervention in the Uesugi conflict and the death of Uesugi Kagetora, Ujimasa forged a new alliance with Oda Nobunaga and Tokugawa Ieyasu. The Hojo clan, alongside these allies, launched an attack on Takeda territory in Suruga, leading to the Battle of Omosu and participation in the Conquest of Koshu, culminating in the Battle of Tenmokuzan in 1582.
After Oda Nobunaga's unexpected death in 1582, Ujimasa seized the opportunity to attack Oda clan territories at the Battle of Kanagawa. Subsequently, the Hojo and Tokugawa clans settled their territorial disputes by exchanging Kai and Shinano Provinces for Kozuke Province.
In 1588, as Toyotomi Hideyoshi succeeded in unifying Japan, he invited Ujimasa and his son Ujinao to an imperial visit at the Jurakudai in Kyoto. However, Ujimasa declined the invitation, proposing a delay until the spring or summer of 1590, which Hideyoshi refused, straining their relations.
By 1590, Ujimasa had consolidated the clan's position and retired, passing leadership to his son Hojo Ujinao, who became the head of the clan and lord of Odawara. That same year, Hideyoshi launched the Odawara Campaign against the Hojo clan.
See also
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Saito Tatsuoki
Saito Tatsuoki (6 September 1548 - 1573) was a daimyo of Mino Province during Japan's Sengoku period and the third-generation lord of the Saito clan. He was the son of Saito Yoshitatsu and grandson of Saito Dosan. His mother was a daughter of Azai Hisamasa, making him a nephew of Azai Nagamasa and a relative of Oda Nobunaga's first wife, Nohime, who was also a daughter of Saito Dosan.
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Kyogoku Tadataka
Kyogoku Tadataka (1593–1637) was a Japanese nobleman and the head of the Kyogoku clan during the early 17th century, a pivotal time marked by the Tokugawa consolidation of power. His childhood name was Kumamaro, and he hailed from a lineage claiming descent from Emperor Uda (868–897). Tadataka was the son of Kyogoku Takatsugu and one of his concubines, with his paternal grandfather being Kyogoku Takayoshi.
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Matsudaira Naomasa
The late Muromachi period, also known as the Sengoku period, was an era of continuous conflict and upheaval, often likened to periods of chaos in Chinese history. This turbulent era was brought to an end by Tokugawa Ieyasu, who, with the support of loyal retainers, established the Edo Shogunate and became the ruler of Japan. Among Ieyasu’s descendants, Naomasa Matsudaira, his grandson, played a significant role during the Osaka Siege. He earned praise from his adversary, Nobushige Sanada (Yukimura Sanada), for his valor as a young warrior and maintained strong relations with successive Tokugawa shoguns.
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Ishikawa Kazumasa
Ishikawa Kazumasa (1534–1609) was a prominent Japanese retainer who began serving Tokugawa Ieyasu during his youth. Their relationship began in 1551 when both were hostages under the Imagawa clan. Kazumasa remained a loyal companion to Ieyasu, participating in key events such as the Siege of Terabe in 1558 and the Siege of Marune in 1560. After Ieyasu broke away from the Imagawa following the latter event, Kazumasa became a trusted retainer and administrator in his service.
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Shimazu Toyohisa
Shimazu Toyohisa (July 1570 – October 21, 1600), also known as Shimazu Tadatoyo, was a samurai of the Shimazu clan and the son of Shimazu Iehisa. He was the nephew of Shimazu Yoshihiro and held command over Sadowara Castle. Known for his valor, Toyohisa participated in numerous key battles of the late Sengoku period, earning recognition for his bravery and tactical acumen.
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Ikeda Terumasa
Ikeda Terumasa (January 31, 1565 – March 16, 1613) was a Japanese daimyo of the early Edo period, recognized by his court title, "Musashi no Kami," and known as the "Shogun of Western Japan." Terumasa, a distinguished military leader, participated in numerous significant battles during the late Azuchi-Momoyama period. His service at the Battle of Sekigahara earned him control over the Himeji domain. Originally named Araokojimaru, he was the son of Ikeda Tsuneoki and the brother of Ikeda Sen. He later became the heir to Ikeda Nobuteru and held Ikejiri Castle in Mino Province.
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Mori Tadamasa
Mori Tadamasa (1570 - July 31, 1634) was a notable military commander during Japan’s Warring States period and an early Edo-period daimyo. Initially, he governed Kawanakajima Domain in Shinano Province (modern-day Nagano Prefecture) and later became the first lord of Tsuyama Domain in Mimasaka Province (now northern Okayama Prefecture). He founded the Mori family line of the Ako Domain. Tadamasa’s family origins trace back to the Genji (Minamoto) clan, specifically the Kawachi-Genji branch from Kawachi Province (in present-day southeastern Osaka Prefecture), a lineage tied to Emperor Seiwa through his ancestor Yorisada Mori, a great-grandson of the famed Minamoto no Yoshiie.
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Sanada Masayuki
Sanada Masayuki (1547 – July 13, 1611) was a daimyo and prominent lord of Japan's Sengoku period. Head of the Sanada clan from Shinano Province, he served the powerful Takeda clan of Kai Province alongside his father and brothers during Takeda Shingen’s leadership. Following the Takeda clan's decline, Masayuki took charge of the Sanada, and despite limited resources, he established his clan as an independent power under the Toyotomi regime by navigating alliances with dominant clans such as the Tokugawa, Hojo, and Uesugi. Renowned as one of his era's greatest strategists, Masayuki achieved notable victories against the Tokugawa forces in the Battle of Kami River and the Siege of Ueda.
