The is a river in Japan 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...

, and empties into the Nagara River

Nagara River

The has its source in the city of Gujō, Gifu Prefecture, and its mouth in the city of Kuwana, Mie Prefecture, Japan. Along with the Kiso River and Ibi River, the Nagara River is one of the Kiso Three Rivers of the Nōbi Plain. Previously, the river was named Sunomata River . With a length of , it...

.

Geography

The river flows from the city of Motosu

Motosu, Gifu

is a city located in the south west of Gifu Prefecture, Japan.As of July 2011, the city has an estimated population of 34,997. The total area is 374.57 km².-History:On October 28, 1891, the Mino-Owari earthquake, the largest earthquake to hit Japan, struck...

, where it takes water from the Neo River

Neo River

The is a river in Japan which flows through Gifu Prefecture, and is part of the Kiso River system. North of Ōno, the river is also called the .-Geography:The river originates on Mount Nōgōhaku, which lies on the border of Gifu and Fukui prefectures...

 and flows south. After running through Hozumi and Ōgaki

Ogaki, Gifu

is a city located in Gifu Prefecture, Japan. It was incorporated as a city on April 1, 1918. As of July 2011, the city has an estimated population of 160,999 and a total area of .Ōgaki was the final destination for the haiku poet Matsuo Bashō...

, it runs parallel to the Nagara River, which it joins in Anpachi

Anpachi, Gifu

is a town located in the Anpachi District, Gifu, Japan.As of July 2011, the town has an estimated population of 15,274. The total area of the town is 18.19 km². The Solar Ark, an over 300m long photovoltaic power generation facility is located in the town....

.

The cherry blossoms on the banks of the river near Sunomata Castle

Sunomata Castle

is a Japanese castle in Ōgaki in Gifu Prefecture. It was constructed by Toyotomi Hideyoshi, one of the generals of Oda Nobunaga, while they were doing a siege on Inabayama Castle in the mid-16th century. Hideyoshi also found a secret path into the castle and they found Saitō Tatsuoki. Oda Nobunaga...

 are well known and are included on a list of the top 33 cherry blossom sites in Gifu Prefecture.

History

• 1530: A large flood shifted the main branch of the original Neo River
  Neo River
  The is a river in Japan which flows through Gifu Prefecture, and is part of the Kiso River system. North of Ōno, the river is also called the .-Geography:The river originates on Mount Nōgōhaku, which lies on the border of Gifu and Fukui prefectures...
  
   to its current route. This same flood created the Sai River.
• 1641: A fight broke out between the owners of the Mushiroda Canal (席田用水 Mushiroda Yōsui) and the Makuwa Canal (真桑用水 Makuwa Yōsui) over water usage from the Sai River. The dispute was settled with the Mushiroda Canal taking 60% of the flow and the Makuwa Canal taking the remaining 40%.
• 1929: The Sai River Incident occurred when residents demonstrated against the prefectural governor for plans to alter the flow of the river.