Amago clan

A branch of the Sasaki clan of the Omi Genji clan, who wielded power in the San'in region during the Muromachi and Sengoku periods. They are also called "Amakouji." It began when Takahisa Sasaki, grandson of Takauji Sasaki (Doyo), ruled over Amako-go, Inukami-gun, Omi Province (Kora-cho, Inukami-gun, Shiga Prefecture) and took the name Amako. His second son, Mochihisa, went down to Izumo as the deputy governor of the Kyogoku clan after the Meitoku Rebellion (1391). His son, Kiyosada, based himself in Toda Gassan Castle (Yasugi, Shimane Prefecture) during the Onin War (1467-1477) and pacified Izumo, expanding his territory and acquiring the right to collect Mihonoseki levies at the eastern end of the Shimane Peninsula, thus solidifying his economic base. Furthermore, his son, Tsunehisa, repeatedly invaded manors and seized dansen lands, eventually banishing the shugo Kyogoku Masataka to Kyoto in 1486 (Bunmei 18), beginning his path to becoming a Sengoku daimyo, and at his peak he is said to have controlled local lords from 11 provinces, from Iwami and Izumo to Harima. However, due to difficulties in organizing the power, in 1541 (Tenbun 10), Tsunehisa's grandson Haruhisa failed in his conquest of the Mori clan in Aki, and conversely, when the Mori clan advanced into Sanin after conquering Suo and Nagato in 1557 (Koji 3), local people defected one after another. Then, in 1566 (Eiroku 9), Tomita Castle fell and Haruhisa's son Yoshihisa surrendered to the Mori clan, bringing an end to the history of the Amago clan's rule over Sanin.

[Ike Toru]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

室町、戦国時代に山陰地方で勢力を振るった、近江源氏(おうみげんじ)佐々木(ささき)氏の一族。「あまこうじ」ともいう。佐々木高氏(たかうじ)（導誉(どうよ)）の孫にあたる高久(たかひさ)が、近江国犬上(いぬかみ)郡尼子郷（滋賀県犬上郡甲良(こうら)町）を領し、尼子を名のったことに始まる。次男持久(もちひさ)は、明徳(めいとく)の乱（1391）後、京極(きょうごく)氏の守護代として出雲(いずも)に下った。その子清定(きよさだ)は、応仁(おうにん)の乱（1467～1477）に際し富田月山(とだがっさん)城（島根県安来(やすぎ)市）に拠(よ)って出雲(いずも)を平定し、所領拡大、島根半島東端の美保関(みほのせき)銭徴収権獲得など、経済的基盤も固めた。さらにその子経久(つねひさ)は荘園(しょうえん)侵略、段銭(たんせん)押領を重ね、ついには1486年（文明18）守護京極政高(まさたか)を京都に追放して戦国大名への道を歩み始め、最盛期には石見(いわみ)、出雲から播磨(はりま)に至る11か国の国人を従えたという。しかし、権力編成に難があったため、1541年（天文10）経久の孫晴久(はるひさ)が安芸(あき)の毛利(もうり)氏征討に失敗し、逆に毛利氏が1557年（弘治3）の周防(すおう)、長門(ながと)征服以降山陰に進出するや、国人は次々と離反した。そして1566年（永禄9）富田城が陥落し、晴久の子義久(よしひさ)が毛利氏に降(くだ)るに及び、尼子氏の山陰支配の歴史はその幕を閉じたのである。

［池　享］

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