Seto Inland Sea

Seto Inland Sea (瀬戸内海 Seto Naikai) is a body of water separating Honshu and Shikoku, two of the main islands of Japan. Before the construction of the Sanyo Main Line, it was the main transportation link between the Kansai region and Kyushu.

Hiroshima prefecture, Yamaguchi prefecture, Okayama prefecture, Kagawa prefecture, and Ehime prefecture all have coasts on the sea. The cities of Hiroshima, Iwakuni, and Matsuyama are also located on the sea.

The Seto Inland Sea region is known for its moderate climate, with a stable year-round temperature and relatively low rainfall levels: the area is often called "the land of fair weather" (晴れの国 hare no kuni). The sea is also famous for its periodic red tides (赤潮 akashio) caused by dense occurrences of certain phytoplankton and resulting in the killing of large numbers of fish that float to the surface.