What is the longest river in Japan?

Japan's longest river is the Shinano River, which starts in the eastern part of Nagano Prefecture, runs throunh central Niigata, and flows into the Sea of Japan in Niigata City.
The Shinano, 367 km from source to mouth, may not be considered long when compared with famous rivers of the world such as the Mississippi (3,780 km), the Danube (2,860 km), and the Rhine (1,320 km), but it is relatively long for the size of the country.
The second longest river, the Tone River, flows for 322 km through the Kanto Plain. The ishikari River in Hokkaido is the third longest, stretching for 268 km.
Japan is a mountainous country and so most of the country's rivers flow rapidly down from the high mountains.