The Kiso River is a river in the Chubu region of Japan roughly 229 km long, flowing through the prefectures of Nagano, Gifu, Aichi, and Mie before emptying into Ise Bay a short distance away from the city of Nagoya. It is the main river among the Kiso Three Rivers and forms a major part of the Nōbi Plain. The valley around the upper portion of th…The Kiso River is a river in the Chubu region of Japan roughly 229 km long, flowing through the prefectures of Nagano, Gifu, Aichi, and Mie before emptying into Ise Bay a short distance away from the city of Nagoya. It is the main river among the Kiso Three Rivers and forms a major part of the Nōbi Plain. The valley around the upper portion of the river forms the Kiso Valley.