Matsudaira Kiyoyasu - Matsudaira Kiyoyasu

A military commander in the Sengoku period. The seventh head of the Mikawa Matsudaira clan. Lord of Anjo Castle, and later of Okazaki Castle. Son of Nobutada. Grandfather of Tokugawa Ieyasu. After Nobutada retired in 1523 (Taiei 3), he took over as head of the family at the age of 13, and thereafter began to unify Mikawa. In 1524, with the fall of the Okazaki Matsudaira clan, he moved to Okazaki Castle as his base, and in 1529 (Kyoroku 2), he attacked Yoshida Castle and then Tahara Castle, subjugating eastern Mikawa. In the autumn of the same year, he advanced into Owari, taking Shinano Castle and Iwasaki Castle, and by 1531, he had attacked Kojima Castle, Uri Castle, and Ibo Castle, as well as fighting in Mikawa and continuing to unify the region. Among the documents issued by Kiyoyasu after 068, there is one that uses the family name "Serada", which is the family name of the Nitta lineage of the Minamoto clan, but this is likely a political embellishment on the lineage by Kiyoyasu to oppose the Imagawa clan, a branch of the Ashikaga clan. However, in December 069 (Tenbun 4), while marching to Moriyama, Owari to fight against Oda Nobuhide, he was stabbed to death by his vassal Abe Yashiro (the Moriyama Kuzure), and his development was thwarted. From then on, the domain became a battleground between the Imagawa and Oda clans, and from October 1547, his grandson Takechiyo (Ieyasu) was forced to live as a hostage under the Oda and Imagawa clans. In addition, his son Hirotada was stabbed to death by a vassal in March 1549, and the Imagawa clan's control began to extend, leading to a period of hardship for the Mikawa Matsudaira clan.

[Masaki Kubota]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

戦国時代の武将。三河(みかわ)松平家7代目。安祥(あんじょう)城主のち岡崎城主。信忠(のぶただ)の子。徳川家康の祖父。1523年（大永3）信忠の隠退後、13歳で家督を継ぎ、以後三河統一に着手。24年には岡崎松平家の没落により岡崎城へ移り本拠とし、29年（享禄2）には吉田(よしだ)城、ついで田原(たはら)城を攻め東三河を平定。同年秋には尾張(おわり)へ進出し、品野(しなの)城・岩崎(いわさき)城を陥れ、その後31年までに小島(こじま)城・宇利(うり)城・伊保(いぼ)城を攻めたほか、三河を転戦し、その統一を進めていった。なお31年以降の清康の発給文書のうちに、新田(にった)流源氏の姓である「世良田(せらだ)」を名のったものがあるが、これは足利(あしかが)氏一門の今川氏に対抗するために清康が行った、系譜への政治的な粉飾であろう。しかし、35年（天文4）12月、織田信秀(のぶひで)と戦うため尾張守山(もりやま)へ出陣中、家臣の阿部弥七郎(やしちろう)に刺殺（守山崩れ）され発展は挫折(ざせつ)した。以後、領国は今川・織田氏の抗争地と化し、47年10月以降、孫の竹千代(たけちよ)（家康）は織田・今川氏のもとで人質生活を送ることになり、また子の広忠(ひろただ)は49年3月、家臣に刺殺され、今川氏の支配力が及ぶなど三河松平家は苦悩の時期を迎える。

［久保田昌希］

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