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.
In 1582, Tadamasa entered the service of Oda Nobunaga as a page but was soon dismissed after a scuffle with a fellow page, with Nobunaga deeming him too young for the position. This dismissal inadvertently spared Tadamasa from involvement in the Honno-ji Incident, where Nobunaga was assassinated. Two years later, in 1584, his older brother Nagayoshi was killed at the Battle of Komaki and Nagakute, and with his other brothers also deceased, Tadamasa inherited the Mori family estate. He was granted a 70,000-koku fief in Mino Province (southern Gifu Prefecture), residing at Kaneyama Castle. In 1587, Toyotomi Hideyoshi awarded him the surname Hashiba, and he was thereafter known as Hashiba Kaneyama Jiju (chamberlain).
During Hideyoshi’s Korean invasions, Tadamasa served as a public works administrator at Nagoya Castle in Kyushu, leading 2,000 troops. Following Hideyoshi’s death, Tadamasa allied with Tokugawa Ieyasu and received the Matsushiro Domain in Shinano Province (valued at 137,000 koku) in 1600. In the same year, he joined Tokugawa’s Hidetada Eastern Army at the Battle of Sekigahara, participating in the siege of Ueda Castle, home of Sanada Masayuki of the Western Army. Tadamasa resumed the Mori surname after the battle and was rewarded with the Tsuyama Domain (180,000 koku) for his service, becoming its first lord.
Tadamasa passed away in 1634, reportedly after developing severe stomach pain following the consumption of a peach, likely due to food poisoning. He was interred at Sangen-in, a sub-temple of Daitoku-ji in Kyoto’s Murasakino, which is also associated with the family of Ishida Mitsunari.
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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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.
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Sanada Nobuyuki
Sanada Nobuyuki was a renowned samurai of the Sengoku period and the eldest son of daimyō Sanada Masayuki. He was the elder brother of the famous warrior Sanada Yukimura. Nobuyuki’s mother was Kansho-in, Masayuki's wife, and he was married to Komatsuhime (Inahime), the daughter of Honda Tadakatsu and the adopted daughter of Tokugawa Ieyasu. Nobuyuki also had two other wives: Seiin-in, his cousin, and Ukyo, the daughter of Tamagawa Hidemasa.
