, is a river on the main island of Honshu in Japan. It flows from the north to the south on the Kantà  plain, merging with . At 176.7 km in length, it is the longest tributary of Tone-gawa. From ancient times, it has been known to cause floods. The river starts in Kinu swamp in the city of Nikkà Â, Tochigi, within Nikkà  National Park.
Due to heavy rainfall for three consecutive days, on 10 September 2015, the river bank was breached, causing a flood, resulting in the death of two people and several more injuries. In Joso city, homes and infrastructure were damaged.
(confluence with Tone River)