The is a river in the Kantō region of Japan. It is 322 km in length (the second longest in Japan after the Shinano) and has a drainage area of 16,840 km² (largest in Japan). It is nicknamed ; Bandō is an obsolete alias of Kanto, and Tarō is a popular given name for the eldest son).

It is sometimes regarded as one of the three greatest rivers of Japan (the other two are the Yoshino in Shikoku and the Chikugo in Kyūshū).

Geography

The source of the river is Mount Ōminakami (大水上山), which straddles the border between Gunma and Niigata Prefectures. It gathers tributaries and pours into the Pacific Ocean at Choshi city in Chiba Prefecture. The Edo River branches away from the river and flows into Tokyo Bay.

Major tributaries of the river include the Agatsuma, Watarase, Kinu, Omoi, and Kokai rivers.

History

The river was once known for its uncontrollable nature, and its route was changed drastically whenever floods occurred. It is hard to trace the ancient route of the river.

The river originally flowed into Tokyo Bay, and tributaries like the Watarase and Kinu had independent river systems. For the sake of water transportation and flood control, extensive construction began in the 17th century, when the Kanto region became the political center of Japan. The present route of the river was determined in the mass during the Meiji period. Its vast watershed is thus largely artificial.

Use

The river was important transport until the advent of the railway in the 19th century. It carried not only local products like soy sauce from Choshi, but also products from the Tohoku region, in order to save time and to avoid risk in the open sea.

Today the river has several dams to supply water for more than 30 million inhabitants of the Tokyo metropolitan area.

Rafting and Kayaking:

Minakami Onsen in Gunma Prefecture, is the source for the Tone River and during the Spring snow melt period, April - June, the river provides consistent grade 4 rapids (on the International Scale of River Difficulty) over a 12km stretch. The river provides some of the best white water rafting and kayaking in Japan and played host to the rafting world cup in Spring 2007. The snow melt swells the river to grade 4 in Spring; in the Summer it is a gentle grade 2. The MomijiKyo section has 7 grade 3-4 rapids in 1 km and is 12 km long in total.