Imagawa clan

A feudal lord of the branch of the Ashikaga clan during the Muromachi and Sengoku periods. It began when Kuniuji, the second son of Kira Nagauji, grandson of Ashikaga Yoshikane (great-grandson of Minamoto no Yoshiie), ruled Imagawa-no-sho in Hazu County, Mikawa Province (Nishio City, Aichi Prefecture) and called himself Imagawa. Kuniuji's grandson Norikuni served in the army of Ashikaga Takauji during the turbulent times of Genko and Kenmu, and was awarded the position of Shugo (military governor) of both Suruga and Totomi Provinces for his military achievements, laying the foundation for their development. His son Ryoshun (Sadayo) contributed to the establishment of the Ashikaga government as a hikitsuke, head of the Samurai-dokoro, and Kyushu Tandai. From then on, as Shugo of Suruga Province, they were tasked with monitoring the Kamakura government of the Muromachi Shogunate, and fought in the Shogunate army in battles such as the Uesugi Zenshu Rebellion, the Eikyou Rebellion, and the Battle of Yuki. During the Onin-Bunmei War (1467-1477), they sided with the Eastern Army and came into conflict with the Shiba clan, Shugo of Totomi Province, who were on the Western Army. It was during the time of Ujichika that they made the transition from Shugo to Sengoku Daimyo, forming a powerful territorial system that also included Totomi Province, and his son Yoshimoto further added Mikawa to his territory, building a golden age as the leading Sengoku Daimyo in the Tokai region. In 1560 (Eiroku 3), Yoshimoto was killed by Oda Nobunaga at Okehazama during the conquest of Owari, and the family's influence gradually declined, eventually being destroyed by the Tokugawa clan in 1569. Their descendants continued to exist as noble families during the Edo period.

[Masaki Kubota]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

室町・戦国時代の足利(あしかが)氏支流の大名。足利義兼(よしかね)（源義家(みなもとのよしいえ)曽孫(そうそん)）の孫吉良長氏(きらながうじ)の次男国氏(くにうじ)が、三河国幡豆(はず)郡今川庄(いまがわのしょう)（愛知県西尾市）を領し今川を称したことに始まる。国氏の孫範国(のりくに)は元弘(げんこう)・建武(けんむ)の動乱期に足利尊氏(たかうじ)に従軍し、その戦功により駿河(するが)・遠江(とおとうみ)両国の守護職(しゅごしき)を与えられ、発展の基礎をつくった。その子了俊(りょうしゅん)（貞世(さだよ)）は、引付、侍所の頭人、九州探題として足利政権の確立に寄与した。以後代々駿河国守護として室町幕府の鎌倉府監視の任にあたり、上杉禅秀(うえすぎぜんしゅう)の乱、永享(えいきょう)の乱、結城(ゆうき)合戦などに幕府軍として出陣、活躍した。応仁(おうにん)・文明(ぶんめい)の乱（1467～77）では東軍にくみし、西軍の遠江国守護斯波(しば)氏と対立した。守護から戦国大名への転換を遂げたのは氏親(うじちか)のときで、遠江国をあわせた強力な領国体制を形成、その子義元(よしもと)はさらに三河を領国に加え、東海一の戦国大名として全盛期を築いた。1560年（永禄3）義元が尾張(おわり)攻略の過程で織田信長に桶狭間(おけはざま)で討たれると、家勢はしだいに衰退し、1569年徳川氏により滅ぼされた。子孫は江戸時代高家(こうけ)として存続した。

［久保田昌希］

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