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.
In 1562, during the Siege of Kaminogo Castle, Kazumasa played a crucial role as Ieyasu successfully negotiated the release of his family from Imagawa Ujizane. Acting as their guardian, Kazumasa undertook this perilous duty with great responsibility. By 1567, Tokugawa forces were divided into two major divisions. Kazumasa was appointed commander of 13 Tokugawa daimyo-vassals, while Sakai Tadatsugu oversaw 18 daimyo-vassals.
Kazumasa fought in several critical battles, including the Battle of Mikatagahara in 1573 and the Battle of Nagashino in 1575. Following Toyotomi Hideyoshi's victory over Shibata Katsuie in 1583, Ieyasu conveyed his congratulations through Kazumasa. However, under Tokugawa orders, Kazumasa and Sakakibara Yasumasa later issued statements denouncing Hideyoshi. Kazumasa served at the Tokugawa headquarters in Komaki during the Komaki-Nagakute Campaign of 1584.
In 1585, Kazumasa became increasingly disillusioned with Ieyasu's defiance of Hideyoshi. Viewing this resistance as reckless, he defected to Hideyoshi’s side. This betrayal forced Ieyasu to overhaul his military organization and defense strategies, as Kazumasa had deep insights into Tokugawa operations.
After Hideyoshi's death and the establishment of the Tokugawa Shogunate, Kazumasa and his family faced punitive measures, losing their fief. Kazumasa eventually retired and spent his remaining years with his son, Ishikawa Yasunaga, until his death in 1609.
See also
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Asano Nagaakira
Asano Nagaakira (March 18, 1586 – October 16, 1632) was a Japanese samurai and daimyō of the early Edo period. He initially ruled Wakayama Domain before being transferred to the Hiroshima Domain, where his family would remain until the Meiji Restoration.
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Takigawa Kazumasu
Takigawa Kazumasu (1525 – October 21, 1586), also known as Takikawa Sakon or Sakonshogen, was a prominent samurai and daimyō of the Sengoku period. He served as a loyal retainer and military commander under Oda Nobunaga and later Toyotomi Hideyoshi. His biological son, Toshimasu, was adopted by Maeda Toshihisa, the elder brother of Maeda Toshiie, and Kazumasu served alongside Toshiie in Nobunaga’s campaigns.
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Sanada Yukitaka
Sanada Yukitaka (c. 1512 – June 8, 1574) was a renowned samurai warrior of the Sengoku period, best known as one of the "Twenty-Four Generals of Takeda Shingen." He was the father of Sanada Nobutsuna and Sanada Masayuki, as well as the grandfather of the legendary Sanada Yukimura, who later served the Toyotomi clan.
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Torii Mototada
Torii Mototada (1539 – September 8, 1600) was a Japanese samurai and daimyo who lived through the Sengoku and late Azuchi–Momoyama periods. A loyal retainer of Tokugawa Ieyasu, he is best remembered for his heroic last stand at the Siege of Fushimi, an event that played a crucial role in shaping Japanese history.
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Toyotomi Hideyori
Toyotomi Hideyori (August 28, 1593 – June 4, 1615) was the son and designated successor of Toyotomi Hideyoshi, the general who first unified Japan. His mother, Yodo-dono, was Oda Nobunaga's niece.
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Okubo Tadanori
Okubo Tadanori (January 13, 1842 – August 10, 1897) was the 9th daimyo of Odawara Domain in Sagami Province (modern-day Kanagawa Prefecture) during the late Edo period. Before the Meiji Restoration, he held the courtesy title of Kaga no Kami.
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Okubo Tadayo
Okubo Tadayo (1532 – October 28, 1594) was a samurai general who served Tokugawa Ieyasu during the Azuchi–Momoyama period and later became the daimyo of Odawara Domain in the early Edo period.
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Araki Murashige
Araki Murashige (1535 – June 20, 1586) was a samurai and retainer of Ikeda Katsumasa, the head of the powerful Settsu-Ikeda clan in Settsu Province. Initially serving under Katsumasa, he aligned himself with Oda Nobunaga after Nobunaga’s successful campaign to establish control over Kyoto.
