Imagawa Yoshimoto

Sengoku daimyo. The third son of Imagawa Ujichika. His mother was the daughter of Nakamikado Nobutane (Jukeini). His childhood name was Hokikumaru. He started out as a monk at Zentoku-ji Temple in Imaizumi, Fuji County, Suruga Province (Fuji City, Shizuoka Prefecture) under the name Baigaku Shoho, and at one time spent training at Kennin-ji Temple and Myoshin-ji Temple in Kyoto. In April 1536 (Tenbun 5), after his elder brother Ujiteru died young, he fought for the family headship with his half-brother Genko Etan (Ryōshin) (the Hanakura Rebellion), and in June of the same year, he defeated him and succeeded the Imagawa family, returning to secular life and taking the name Yoshimoto. In February of the following year, he married the daughter of Takeda Nobutora and formed an alliance with him, but this prompted his previous ally Hojo Ujitsuna to invade eastern Suruga, leading to a battle for control of the area east of the Fuji River (the Kawahigashi War), and he regained control of the region in 1545. Meanwhile, when the power of Oda Nobuhide in Owari expanded and put pressure on the Matsudaira clan of Mikawa, he came to their aid, dispatching troops to Mikawa and fighting against the Oda clan on many occasions, including the Battle of Azukizaka in 1542 and 1548 (Anjo City, Aichi Prefecture). During this process, he conquered Yoshida Castle (Toyohashi) in eastern Mikawa, occupied Okazaki Castle of the Matsudaira clan in 1549, and then captured Anjo Castle, which had been a subsidiary castle of the Oda clan. In a hostage exchange, he welcomed Matsudaira Takechiyo (Tokugawa Ieyasu), who was under the Oda clan, to Sunpu. By the end of the Tenbun era (1532-1555), he had succeeded in taking over almost all of Mikawa in addition to Suruga and Totomi, and steadily strengthened his control as his territory expanded. Examples of this include the implementation of land surveys, control of vassals and temples and shrines, commerce and industry, horse-drawn carriage policies, and mine development. The passage in Article 20 of the Kana Mokuroku Supplement, enacted in 1553, which reads, "I am now proposing the laws of the country to the best of my ability," shows his confidence as the greatest warring lord in the Tokai region. Yoshimoto, who was aiming to advance westward, also aimed to stabilize the political situation in the eastern part of his domain, and in 54 he formed a tripartite alliance with Hojo Ujiyasu and Takeda Harunobu (Shingen) through a political marriage (the Koshu-Suruga Alliance). In 58 (Eiroku 1), he assigned control of Suruga and Totomi to his son Ujizane, and planned to control Mikawa and make Owari his domain. The development of the Imagawa clan was based on this series of domestic and foreign affairs and cooperation. However, in May 60, Yoshimoto mobilized the military forces of Suruga, Totomi, and Owari to invade Owari, capturing the Oda forces at Marune and Washizu Forts, and on the 19th of the same month, when he had just moved his headquarters to Okehazama (Toyoake City, Aichi Prefecture), he was attacked by Oda Nobunaga and died a heroic death in battle. His posthumous name is Tenzawajidono Shuho Tetsuko Daikoji.

Furthermore, early modern historical documents do not portray Yoshimoto as a capable Sengoku daimyo, as he took the divine lord Ieyasu hostage in order to serve the shogunate. However, based on the historical materials that remain from that time, it can be said that Yoshimoto was one of the most capable Sengoku daimyo.

[Masaki Kubota]

"Imagawa Yoshimoto" by Kojima Hirotsugu (1966, Jinbutsu Oraisha)" ▽ "The Suruga Imagawa Clan" by Owada Tetsuo (1983, Shinjinbutsu Oraisha)" ▽ "The Imagawa Research Group, ed., "The Imagawa Clan of Suruga" Volumes 1-6 (1975-82, Shizuoka Yajimaya)"

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

戦国大名。今川氏親(うじちか)の三男。母は中御門宣胤(なかみかどのぶたね)の女(むすめ)（寿桂尼(じゅけいに)）。幼名は芳菊丸。最初駿河(するが)国富士郡今泉（静岡県富士市）の善徳寺の僧として梅岳承芳(ばいがくしょうほう)と称し、一時は京都建仁寺、妙心寺で修養を重ねた。1536年（天文5）4月に兄氏輝(うじてる)が早世すると異母兄の玄広恵探(げんこうえたん)（良真(りょうしん)）と家督を争い（花倉(はなくら)の乱）、同年6月これを倒し今川家を継ぎ、還俗(げんぞく)して義元と名のった。翌年2月、武田信虎(のぶとら)の女をめとり同盟を結んだが、これを契機に、従来同盟関係にあった北条氏綱(うじつな)が駿河東部に侵攻したため、以後富士川以東の支配をめぐって戦い（河東一乱）、45年同地域の支配を回復する。一方、尾張(おわり)の織田信秀(おだのぶひで)の勢力拡大により三河松平氏が圧迫されると、これを援助し三河へ出兵、42年、48年の小豆坂(あずきざか)合戦（愛知県安城市）をはじめ、織田氏としばしば戦っている。この過程で東三河の吉田（豊橋）城を制圧、49年には松平氏の岡崎城を占領し、ついで織田氏の支城となっていた安祥(あんじょう)城を奪取し、その際の人質交換により織田氏のもとにいた松平竹千代（徳川家康）を駿府(すんぷ)に迎えた。天文(てんぶん)（1532～55）末期にはそれまでの駿河、遠江(とおとうみ)に加えて、ほぼ三河の領国化に成功し、領国の拡大とともに支配体制を着実に強化していった。検地の実施、家臣団・寺社統制、商工業・伝馬(てんま)政策、鉱山開発などはその例であり、53年制定の仮名目録追加第20条にみられる「只今(ただいま)はをしなべて自分の力量を以(もっ)て国の法度(はっと)を申付」という一節は、東海一の戦国大名としての自信を表している。また西進を目ざす義元は領国東部の政治的安定を意図し、54年には政略結婚による北条氏康(うじやす)、武田晴信(はるのぶ)（信玄(しんげん)）との三者同盟を完成させ（甲相駿同盟）、さらに58年（永禄1）には駿遠支配を子息氏真(うじざね)に分掌させ、自らは三河支配と尾張領国化を策した。今川氏の発展はこうした一連の内政と外交の充実、連携に基因していたといえる。しかし60年5月、駿遠三の兵力を動員し尾張へ侵入した義元は、織田方の丸根(まるね)・鷲津砦(わしづとりで)を陥落させ、同月19日、本陣を桶狭間(おけはざま)（愛知県豊明(とよあけ)市）に移したところで織田信長の急襲を受け、壮烈な戦死を遂げた。法名天沢寺殿秀峰哲公大居士。

　なお近世史書類は、幕府の手前、神君家康を人質とした義元を戦国大名の器量として描いていないが、残された当時の史料による限り、義元はもっとも有能な戦国大名の一人だったといえる。

［久保田昌希］

『小島広次著『今川義元』（1966・人物往来社）』▽『小和田哲男著『駿河今川一族』（1983・新人物往来社）』▽『今川氏研究会編『駿河の今川氏』1～6集（1975～82・静岡谷島屋）』

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