The is a river located on the western side of the island of Iriomote, one of the Yaeyama Islands of Japan.
The mean annual temperature is 23.4 ðC, and the mean annual rainfall during the period 1979 to 2000 was 2342 mm / year.
The river's estuary and shoreline supports three mangrove species, Bruguiera gymnorhiza , Rhizophora stylosa and Kandelia candel