Oi River
Encyclopedia
Shizuoka Prefecture
is a prefecture of Japan located in the Chūbu region on Honshu island. The capital is the city of Shizuoka.- History :Shizuoka prefecture was formed from the former Tōtōmi, Suruga and Izu provinces.The area was the home of the first Tokugawa Shogun...
, 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...
.
Geography
The Ōi River flows from the Akaishi MountainsAkaishi Mountains
is a mountain range in central Honshū, Japan, bordering Nagano, Yamanashi and Shizuoka prefectures. It is also called the , as it joins with the Hida Mountains and the Kiso Mountains to form the Japanese Alps....
, the branch of the Japanese Southern Alps which form the border between Shizuoka, Nagano
Nagano Prefecture
is a prefecture of Japan located in the Chūbu region of the island of Honshū. The capital is the city of Nagano.- History :Nagano was formerly known as the province of Shinano...
and Yamanashi
Yamanashi Prefecture
is a prefecture of Japan located in the Chūbu region of the island of Honshū. The capital is the city of Kōfu.-Pre-history to the 14th century:People have been living in the Yamanashi area for about 30,000 years...
prefectures. These mountains, with peaks ranging from 2000–3000 meters, are characterized by heavy rainfall (up to 3000 mm per year) and deep V-shaped valleys. The river follows a generally southern course, with seven wide bends in its central region, before exiting into Suruga Bay
Suruga Bay
Suruga Bay is a bay on the Pacific coast of Honshū in Shizuoka Prefecture, Japan. It is situated north of an imaginary line joining Omaezaki Point and Irōzaki Point at the tip of the Izu Peninsula and surrounded by Honshū to the southwest and west and the Izu Peninsula to the east.-Geology:Suruga...
in the Philippine Sea
Philippine Sea
The Philippine Sea is a marginal sea east and north of the Philippines occupying an estimated surface area of 2 million mi² on the western part of the North Pacific Ocean...
.
History
The Ōi River is mentioned in Nara periodNara period
The of the history of Japan covers the years from AD 710 to 794. Empress Gemmei established the capital of Heijō-kyō . Except for 5 years , when the capital was briefly moved again, it remained the capital of Japanese civilization until Emperor Kammu established a new capital, Nagaoka-kyō, in 784...
records as forming the border between Tōtōmi
Totomi Province
was a province of Japan in the area of Japan that is today western Shizuoka Prefecture. Tōtōmi bordered on Mikawa, Suruga and Shinano Provinces. Its abbreviated form name was .-History:...
and Suruga Province
Suruga Province
was an old province in the area that is today the central part of Shizuoka prefecture. It was sometimes called . Suruga bordered on Izu, Kai, Sagami, Shinano, and Tōtōmi provinces; and had access to the Pacific Ocean through Suruga Bay.-History:...
s. However, due to shifting of the course of the river over the centuries, by the late Muromachi period
Muromachi period
The is a division of Japanese history running from approximately 1336 to 1573. The period marks the governance of the Muromachi or Ashikaga shogunate, which was officially established in 1338 by the first Muromachi shogun, Ashikaga Takauji, two years after the brief Kemmu restoration of imperial...
, this was not always the case.
During the Edo period
Edo period
The , or , is a division of Japanese history which was ruled by the shoguns of the Tokugawa family, running from 1603 to 1868. The political entity of this period was the Tokugawa shogunate....
, the Tōkaidō
Tokaido (road)
The ' was the most important of the Five Routes of the Edo period, connecting Edo to Kyoto in Japan. Unlike the inland and less heavily travelled Nakasendō, the Tōkaidō travelled along the sea coast of eastern Honshū, hence the route's name....
developed as the major highway linking Edo
Edo
, also romanized as Yedo or Yeddo, is the former name of the Japanese capital Tokyo, and was the seat of power for the Tokugawa shogunate which ruled Japan from 1603 to 1868...
with Kyoto
Kyoto
is a city in the central part of the island of Honshū, Japan. It has a population close to 1.5 million. Formerly the imperial capital of Japan, it is now the capital of Kyoto Prefecture, as well as a major part of the Osaka-Kobe-Kyoto metropolitan area.-History:...
, and daimyo
Daimyo
is a generic term referring to the powerful territorial lords in pre-modern Japan who ruled most of the country from their vast, hereditary land holdings...
from the western domains were forced to travel on a regular basis to Edo to attend to the Shogun
Shogun
A was one of the hereditary military dictators of Japan from 1192 to 1867. In this period, the shoguns, or their shikken regents , were the de facto rulers of Japan though they were nominally appointed by the emperor...
in a system known as sankin kōtai
Sankin kotai
was a policy of the shogunate during most of the Edo period of Japanese history. The purpose was to control the daimyo. In adopting the policy, the shogunate was continuing and refining similar policies of Toyotomi Hideyoshi. In 1635, a law required sankin kōtai, which was already an established...
. However, the Tokugawa shogunate
Tokugawa shogunate
The Tokugawa shogunate, also known as the and the , was a feudal regime of Japan established by Tokugawa Ieyasu and ruled by the shoguns of the Tokugawa family. This period is known as the Edo period and gets its name from the capital city, Edo, which is now called Tokyo, after the name was...
prohibited the building of bridges over major rivers as a security measure, and in the case of the Ōi River, even ferryboats were forbidden. As depicted in contemporary ukiyoe prints by artists such as Hokusai
Hokusai
was a Japanese artist, ukiyo-e painter and printmaker of the Edo period. He was influenced by such painters as Sesshu, and other styles of Chinese painting...
, travelers crossed the river on bearers' shoulders or on horseback. In cases of bad weather or high waters, they were forced to stay several days (or even several weeks) beside the river at post stations
Shukuba
were post stations during the Edo period in Japan, generally located on one of the Edo Five Routes or one of its sub-routes. They were also called shukueki . These post stations were places where travelers could rest on their journey around the nation...
such as Shimada-juku
Shimada-juku
was the twenty-third of the fifty-three stations of the Tōkaidō. It is located in what is now part of Shimada, Shizuoka Prefecture, Japan.-History:...
or Kanaya-juku
Kanaya-juku
was the twenty-fourth of the fifty-three stations of the Tōkaidō. It is located in what is now part of Shimada, Shizuoka Prefecture, Japan. During the Edo period, it was the easternmost post station of Tōtōmi Province.-History:...
.
Because of this, the Ōi River was regarded as a black spot of the Tōkaidō. A well-known lyric states:
- 箱根八里は馬でも越すが、越すに越されぬ大井川
- Hakone hachiri wa uma demo kosu ga, kosu ni kosarenu Ōigawa
- Even horses can cross eight riJapanese units of measurement' is the traditional Japanese system of measurement. The name shakkanhō originates from the name of two of the units, the shaku, a unit of length, and the kan, a mass measurement.The system is Chinese in origin...
(=31 km) of Hakone, but the Ōi River is hard to get over in any way.
The river was bridged shortly after the Meiji Restoration
Meiji Restoration
The , also known as the Meiji Ishin, Revolution, Reform or Renewal, was a chain of events that restored imperial rule to Japan in 1868...
, notably by the Hōrai Bridge
Horai Bridge
The constructed in 1879 is a wooden walking bridge in Shimada, Shizuoka Prefecture, Japan over the Ōi River. The bridge was registered in The Guinness Book of Records as the longest wooden walking bridge in 1997.-External links:*...
in 1879 (which was listed as the world’s longest wooden pedestrian bridge by the Guinness Book
Guinness World Records
Guinness World Records, known until 2000 as The Guinness Book of Records , is a reference book published annually, containing a collection of world records, both human achievements and the extremes of the natural world...
, and by other road and railroad bridges. Today the Tōkaidō Shinkansen express train
Express train
Express trains are a form of rail service. Express trains make only a small number of stops, instead of stopping at every single station...
crosses the river in a few seconds.
Hydroelectric development
The potential of the Ōi River valley for hydroelectric power development was realized by the Meiji government at the start of the 20th century. The Ōi River was characterized by a high volume of flow and a fast current. Its mountainous upper reaches and tributaries were areas of steep valleys and abundant rainfall, and were sparsely populated.In 1906, a joint venture
Joint venture
A joint venture is a business agreement in which parties agree to develop, for a finite time, a new entity and new assets by contributing equity. They exercise control over the enterprise and consequently share revenues, expenses and assets...
company, the was established with private investors, and began studies and design work on plans to exploit the potential of both the Ōi River and Fuji River
Fuji River
The is a river in Yamanashi and Shizuoka Prefectures of central Japan. It is long and has a watershed of . With the Mogami River and the Kuma River, it is regarded as one of the three most rapid flows of Japan....
in Shizuoka Prefecture, and a small power station was built in 1911. However, 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...
and Tenryū River
Tenryu River
The is a river arising from Lake Suwa in Okaya, Nagano Prefecture, grazing Aichi Prefecture and flowing through western Shizuoka Prefecture in central Honshū, Japan. With a length of , it is Japan's ninth longest river.-Geography:...
attracted more investment, and the company did not flourish. The British interests were bought out by 1921, and the company was renamed , for its plan to divert water from the Ōi River to the Hayakawa River in Yamanashi Prefecture
Yamanashi Prefecture
is a prefecture of Japan located in the Chūbu region of the island of Honshū. The capital is the city of Kōfu.-Pre-history to the 14th century:People have been living in the Yamanashi area for about 30,000 years...
through a system of penstock
Penstock
A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydraulic turbines and sewerage systems. It is a term that has been inherited from the technology of wooden watermills....
s, and thus generate electricity. Work on the Tashiro Dam
Tashiro Dam
The is a dam on the Ōi River in Aoi-ku, Shizuoka, Shizuoka Prefecture on the island of Honshū, Japan. It was the first concrete gravity dam to be constructed on the Ōi River, and has a hydroelectric power generating station owned by the Tokyo Electric Power Company....
began in 1924 and was completed in 1928. Hayakawa Electric became a subsidiary of Tokyo Electric in 1925 and was renamed Ōigawa Electric before becoming nationalized and merged with other electrical producers into the in 1938. During the early 1930s, Ōigawa Electric had completed a number of dams on tributary branches of the Ōi River, but work was stalled by the Great Depression
Great Depression
The Great Depression was a severe worldwide economic depression in the decade preceding World War II. The timing of the Great Depression varied across nations, but in most countries it started in about 1929 and lasted until the late 1930s or early 1940s...
, and came to a halt during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
After the end of World War II, the American occuption authorities
Supreme Commander of the Allied Powers
Supreme Commander of the Allied Powers was the title held by General Douglas MacArthur during the Occupation of Japan following World War II...
ordered the dissolution of Nippon Hassoden, which was divided into regional power companies. Central Japan came under Chubu Electric Power, which inherited the various dams and projects on the Ōi River (with the exception of Tashiro Dam). In part through foreign aid loans from the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...
, Chubu Electric pioneered the use of new dam technologies, such as the hollow-core concrete gravity dam concept at the Ōi River, and completed a number of large dams in the 1950s and early 1960s. These dams have altered the once abundant flow of the river, and the lower reaches of the river near its mouth are almost dry.
Tourism
The Ōigawa RailwayOigawa Railway
The is a railway company in Shizuoka Prefecture, Japan. The company is commonly known as . The company belongs to Meitetsu Group. The first section of its lines opened in 1927....
runs two lines in the Ōi River valley. Originally built to facilitate dam construction, both lines are now primarily run for tourists, and include a popular steam locomotive
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
run into the mountains.