Iwamatsu River

…The town borders Kochi Prefecture to the east. It is surrounded by mountains on three sides, and there are lowlands along rivers such as the Iwamatsu River, which originates from Onigajoyama (1,151m) at the northern end of the town and flows into the Uwa Sea. The area was called Tsushima-go, and the Ochi clan, who ruled the area from Amagamori Castle in Iwamatsu in the Middle Ages, were called Tsushima-dono. …

*Some of the terminology that refers to "Iwamatsu River" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…東は高知県に接する。三方を山に囲まれ，町域北端の鬼ヶ城山(1151m)に発して宇和海に注ぐ岩松川などの河川沿いに低地がある。一帯は津島郷とよばれ，中世，岩松の天ヶ森城に拠ってあたりを支配した越智氏は，津島殿と称された。…

※「岩松川」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報