The is a river in Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 which flows through Gifu Prefecture

Gifu Prefecture

is a prefecture located in the Chūbu region of central Japan. Its capital is the city of Gifu.Located in the center of Japan, it has long played an important part as the crossroads of Japan, connecting the east to the west through such routes as the Nakasendō...

. It is part of the Kiso River

Kiso River

The is a river in Japan roughly 193 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 of the Kiso Three Rivers and forms a major part of the Nōbi Plain...

 system.

Geography

The river originates from Mount Yaki on the border of Nakatsugawa

Nakatsugawa, Gifu

is a city located in the Tōnō region of Gifu Prefecture, Japan. The city was founded on April 1, 1952.-History:During Japan's Edo period, Nakatsugawa was a post town, known as Nakatsugawa-juku, one of the 69 Stations of the Nakasendō along the Nakasendō. The travel route ran from the Nihonbashi in...

 and Ena

Ena, Gifu

is a city located in the Tōnō region of Gifu Prefecture, Japan. As of July 2011, the city has an estimated population of 53,378. The total area is 504.19 km²....

 and flows west. It flows through the Akigawa Dam and the Ōi Dam

Oi Dam

The is a dam located between the cities of Ena and Nakatsugawa in Gifu Prefecture, Japan. It was built to produce electricity for the surrounding area. The Agi River flows through the damn....

 before emptying into the Kiso River

Kiso River

The is a river in Japan roughly 193 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 of the Kiso Three Rivers and forms a major part of the Nōbi Plain...

.

History

Ōi-juku

Oi-juku

was the forty-sixth of the sixty-nine stations of the Nakasendō. It is located in the present-day city of Ena, Gifu Prefecture, Japan. From Ōi-juku to the next post town, Ōkute-juku, there are 13 hills to pass over...

, a post town

Post town

A post town is a required part of all postal addresses in the United Kingdom, and a basic unit of the postal delivery system. Including the correct post town in the address increases the chances of a letter or parcel being delivered on time. Post towns are usually based upon the location of...

 on the historical Nakasendō

Nakasendo

The , also called the , was one of the five routes of the Edo period, and one of the two that connected Edo to Kyoto in Japan. There were 69 stations between Edo and Kyoto, crossing through Musashi, Kōzuke, Shinano, Mino and Ōmi provinces...

, was on the banks of the Agi River.

River communities

The Agi river flows through the cities of Ena

Ena, Gifu

is a city located in the Tōnō region of Gifu Prefecture, Japan. As of July 2011, the city has an estimated population of 53,378. The total area is 504.19 km²....

 and Nakatsugawa

Nakatsugawa, Gifu

is a city located in the Tōnō region of Gifu Prefecture, Japan. The city was founded on April 1, 1952.-History:During Japan's Edo period, Nakatsugawa was a post town, known as Nakatsugawa-juku, one of the 69 Stations of the Nakasendō along the Nakasendō. The travel route ran from the Nihonbashi in...

in Gifu Prefecture.