Kaminoirōgawa River

...A river that flows almost southwest through the center of eastern Kochi Prefecture and empties into Tosa Bay. The Makiyama River originates on the eastern slope of Mt. Shirakami (1,770m) in the northeastern part of Monobe Village, Kami County, flows south through Befu Gorge in Tsurugiyama Quasi-National Park, known for its beautiful valley, then turns southwest and merges with the Kaminiro River, which originates on the southern slope of Mt. Sanrei (1,893m) on the border with Tokushima Prefecture, at Otori, the center of Monobe Village, passes through Kohoku Town, turns south near Suita in Tosayamada Town, enters the Konaga Plain (Kochi Plain), and empties into Tosa Bay at Yoshikawa Village. The Makiyama River is collectively called the Monobe River from its source to its mouth, but sometimes it is called the Monobe River after it merges with the Otori.

*Some of the terminology that refers to "Kami-Nirogawa" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…高知県東部中央をほぼ南西流して土佐湾に注ぐ川。香美郡物部村北東部の白髪山(1770m)の東斜面に源を発した槙山川が，渓谷美で知られる剣山国定公園中の別府（べふ）峡を南流，さらに南西に向きを変えて物部村の中心地大栃で，徳島県境の三嶺（さんれい）(1893m)の南斜面に源を発する上韮生（かみにろう）川と合流，香北町を経て土佐山田町杉田（すいた）付近で南に方向を転じ，香長平野(高知平野)に出て吉川村で土佐湾に注ぐ。槙山川の水源地から河口までを物部川と総称するが，大栃で合流して以後を物部川とする場合もある。…

※「上韮生川」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