
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.
In 1579, during the Siege of Itami, Terumasa and his father guarded Settsukura Bridge, and during the 1580 Siege of Hanakuma Castle, Terumasa distinguished himself in combat by personally defeating six enemies, earning him commendation from Oda Nobunaga. During the Battle of Nagakute in 1584, Terumasa initially fought under Ikeda Tsuneoki and Mori Nagayoshi but ultimately had to retreat following their defeat.
In 1590, following Tokugawa Ieyasu’s move to the Kanto region, Terumasa was awarded a 152,000-koku fief at Yoshida in Mikawa Province. In 1594, he married Tokuhime, daughter of Tokugawa Ieyasu, aligning the Ikeda clan closely with the Tokugawa. That same year, he was involved in logistical support for Hideyoshi’s Korean campaigns and contributed to constructing Fushimi Castle and Yamatotanai Castle for Hideyasu.
After Hideyoshi’s death in 1598, Terumasa allied with Tokugawa Ieyasu, joining a coalition against Ishida Mitsunari, a conflict rooted in disputes over campaign assessments from the Imjin War. While traditionally viewed as a conspiracy to kill Mitsunari, modern historians argue this was a legal dispute mediated by Ieyasu, who intervened to protect Mitsunari from escalation. Tensions between Mitsunari’s faction and Tokugawa supporters contributed to the later Sekigahara conflict.
During the Sekigahara Campaign in 1600, Terumasa supported Tokugawa, convincing Nakagawa Hidenari to do the same. His forces crossed Kawada River and defeated Oda Hidenobu’s forces. At Sekigahara, Terumasa commanded 4,560 troops in the rear guard, facing minor skirmishes with Chosokabe Morichika’s forces. Following the Tokugawa victory, he received the province of Harima and expanded Himeji Castle, completing it in 1609. Bizen Province was added to Terumasa’s territories, which he entrusted to his eldest son, Toshitaka.
By Terumasa’s death in 1613, the Ikeda clan governed an expansive domain that included Harima, Bizen, Inaba, and Awaji, with a combined income of roughly 1,000,000 koku. After Toshitaka’s passing, the Tokugawa Bakufu moved to curtail the Ikeda clan's power, restricting them to the domains of Tottori and Okayama. Terumasa’s legendary katana, known as "Okanehira," was noted for its remarkable size and craftsmanship by Kanehira of Bizen Province, symbolizing the Ikeda legacy.
See also
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Tokugawa Iemochi

Tokugawa Iemochi (1846–1866) was the fourteenth shōgun of the Tokugawa shogunate and ruled from 1858 until his death. His reign came during the turbulent final years of the shogunate, when Japan faced growing Western pressure and serious internal political conflict.
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Tokugawa Ienari

Tokugawa Ienari (1773–1841) was the eleventh shōgun of the Tokugawa shogunate and ruled from 1787 to 1837, making him the longest-serving Tokugawa shōgun. He was a great-grandson of the eighth shōgun, Tokugawa Yoshimune.
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Matsudaira Nobuyasu

Matsudaira Nobuyasu was only twenty years old when his father ordered him to commit seppuku. The reason was not a defeat in battle, but a crisis inside the Tokugawa family that had become too dangerous to ignore.
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Yamagata Masakage

Masakage was one of Takeda Shingen’s most loyal and capable commanders. He was included in the famous list of the “Twenty-Four Generals of Takeda Shingen” and also belonged to the inner circle of four especially trusted warlords known as the Shitennō.
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Yagyu Munenori

Yagyū Munenori began his service under Tokugawa Ieyasu while his father, Yagyū Muneyoshi, was still at his side. In 1600, Munenori took part in the decisive Battle of Sekigahara. As early as 1601, he was appointed a kenjutsu instructor to Tokugawa Hidetada, Ieyasu’s son, who later became the second shogun of the Tokugawa clan.
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Yagyu Muneyoshi

A samurai from Yamato Province, he was born into a family that had been defeated in its struggle against the Tsutsui clan. Muneyoshi first took part in battle at the age of sixteen. Due to circumstances beyond his control, he was forced to enter the service of the Tsutsui house and later served Miyoshi Tōkei. He subsequently came under the command of Matsunaga Hisahide and in time became a vassal first of Oda and later of Toyotomi.
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Endo Naozune

Naozune served under Azai Nagamasa and was one of the clan’s leading vassals, renowned for his bravery and determination. He accompanied Nagamasa during his first meeting with Oda Nobunaga and at that time asked for permission to kill Nobunaga, fearing him as an extremely dangerous man; however, Nagamasa did not grant this request.
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Hosokawa Sumimoto

Sumimoto came from the Hosokawa clan: he was the biological son of Hosokawa Yoshiharu and at the same time the adopted son of Hosokawa Masamoto, the heir of Hosokawa Katsumoto, one of the principal instigators of the Ōnin War. Masamoto was homosexual, never married, and had no children of his own. At first he adopted Sumiyuki, a scion of the aristocratic Kujō family, but this choice provoked dissatisfaction and sharp criticism from the senior vassals of the Hosokawa house. As a result, Masamoto changed his decision and proclaimed Sumimoto as his heir, a representative of a collateral branch of the Hosokawa clan that had long been based in Awa Province on the island of Shikoku. Almost immediately after this, the boy became entangled in a complex and bitter web of political intrigue.
