Seto Inland Sea - History

History

It is believed that in the last ice age the sea level was lower than today. After the ice age, sea water poured into a lower part between the Chūgoku mountains and Shikoku mountains and formed the Inland Sea as we know it today.

From ancient times, the Inland Sea served as a main transport line between its coastal areas, including what is today the Kansai region and Kyūshū. It was also a main transport line between Japan and other countries, including Korea and China. Even after the creation of major highways such as the Nankaidō and San'yodo, the Inland Sea remained a major transport route. There are records that some foreign emissaries from China and Korea sailed on the Inland Sea.

Due to the importance of water traffic, regional powers often had their own private navies. In many documents, these navies were called suigun (水軍?, lit. "water army"), or simply pirates. Sometimes they were considered to be public enemies, but in most cases they were granted the right to self-governance as a result of their strength.

In the 12th century, Taira no Kiyomori planned to move the capital from Kyoto to the coastal village of Fukuhara (today Kobe) to promote trade between Japan and the Song Dynasty of China. This transfer was unsuccessful, and soon after Kyoto became the capital again. Later, the Battle of Yashima took place off the coast of present-day Takamatsu.

During the feudal period, suigun seized power in most coastal areas. The Kono in Iyo province (today Ehime prefecture) and Kobayakawa (later Mori) in Aki province (today a part of Hiroshima prefecture) clans were two of the more famous suigun lords.

In the Edo period, the Inland Sea was one of the busiest transport lines in Japan. It was a part of a navigational route around Japan's islands via the Sea of Japan. Many ships navigated from its coastal areas to the area along the Sea of Japan. It was not only the main transport line between Kansai and Kyūshū, but also for Hokuriku, Tōhoku, and even Hokkaidō (which was called Ezo at the time). Major ports in the Edo period were Osaka, Sakai, Shimotsui, Ushimado, and Tomonoura. The Inland Sea also served many daimyo in the western area of Japan as their route to and from Edo, to fulfill their obligations under sankin-kōtai. Many used ships from Osaka. Thanks to transport through the Inland Sea, Osaka became the economic center of Japan. Each han had an office called Ozakayashiki in Osaka. These Ozakayashiki were among Japan's earliest forms of banks, facilitating domestic trade and helping to organize the income of the daimyo, which was in the form of koku, giant bales of rice.

The Inland Sea was also part of the official Chosendentsushi route, bringing Korean emissaries to the Shogunate.

After the Meiji Restoration, the coastal areas of the Inland Sea were rapidly industrialized. One of the headquarters of the Japanese Navy was built in the town of Kure. Since the Meiji period, development of land transport has been reducing the importance of the Inland Sea as a transport line. Remarkable land transportation innovations include the Sanyō Main Railroad Line in Honshū and the Yosan Main Railroad Line in Shikoku (both completed before World War II) and three series of bridges connecting Honshū and Shikoku (completed in the late 20th century). The Inland Sea is still used, however, by an international cargo transport line and several local transport lines connecting Honshū with Shikoku and Kyūshū.