The is a river which flows through the northwest quadrant of central Tokyo, Japan. Its source is in the district of Hana-koganei-minami-cho, in the city of Kodaira. At Horifune, Kita-ku, it empties into the Sumida River. With a total length of 25.2 km and a watershed of 61.6 km², it is categorized as a 1st class river by the Japanese government.