is the smallest (225 km long and between 50 and 150 km wide) and least populous (4,141,955 as of 2005) of the four main islands of Japan, located south of Honshū and east of Kyūshū island. Its ancient names include Iyo-no-futana-shima (伊予之二名島), Iyo-shima (伊予島), and Futana-shima (二名島). The current name refers to the four former provinces which made up the island: Awa, Tosa, Sanuki, and Iyo.
The 50th largest island by area, Shikoku is smaller than Sardinia and Bananal, but larger than Halmahera and Seram. By population, it ranks 23rd, having fewer inhabitants than Sicily or Singapore, but more than Puerto Rico or Negros.
Mountains running east and west divide Shikoku into a narrow northern subregion, fronting on the Inland Sea, and a southern part facing the Pacific Ocean. Most of the 4.5 million inhabitants live in the north, and all but one of the island's few larger cites are located there. Mount Ishizuchi (石鎚山) in Ehime at is the highest mountain on the island. Industry is moderately well developed and includes the processing of ores from the important Besshi copper mine. Land is used intensively. Wide alluvial areas, especially in the eastern part of the zone, are planted with rice and subsequently are double cropped with winter wheat and barley. Fruit is grown throughout the northern area in great variety, including citrus fruits, persimmons, peaches, and grapes. Because of wheat production Sanuki udon (讃岐うどん) became an important part of the diet in Kagawa Prefecture (former Sanuki Province) in the Edo period.
The larger southern area of Shikoku is mountainous and sparsely populated. The only significant lowland is a small alluvial plain at Kōchi, the prefectural capital. The area's mild winters stimulated some truck farming, specializing in growing out-of-season vegetables under plastic covering. Two crops of rice can be cultivated annually in the southern area. The pulp and paper industry took advantage of the abundant forests and hydroelectric power.
Shikoku has four important capes. Gamōda in Anan, Tokushima is the easternmost point on the island, and Sada in Ikata, Ehime the westernmost. Muroto in Muroto, Kochi and Ashizuri, the southern extreme of Shikoku, in Tosashimizu, Kochi, jut into the Pacific Ocean. The island's northernmost point is in Takamatsu, Kagawa.
The eastern gateway to Shikoku, Naruto City in Tokushima Prefecture has been linked to the Kobe-Awaji-Naruto Expressway since 1998. This line connects Shikoku to the Kansai area which has a large population, including the large conurbations of Osaka, Kyoto and Kobe. Therefore, the Kobe-Awaji-Naruto Expressway carries a large traffic volume. Many highway buses are operated between Kansai and Tokushima Prefecture. The central part of Shikoku is connected to Honshū by ferry, air and since 1988, by the Great Seto Bridge network. Until completion of the bridges, the region was isolated from the rest of Japan. The freer movement between Honshū and Shikoku was expected to promote economic development on both sides of the bridges, which has not materialized yet.
The Shikoku Railway Company (JR Shikoku) serves the island. JR lines include:
Private railway lines operate in each of the four prefectures on Shikoku.
Shikoku lacks a full international airport but has 4 regional airports (Tokushima, Takamatsu, Kochi-Ryoma and Matsuyama Airport). All of these airports have flights to Tokyo and other major Japanese cities such as Osaka, Nagoya, Sapporo, and Fukuoka. International flights to Seoul, South Korea are serviced by Asiana Airlines from Matsuyama and Takamatsu. There are periodic international charter flights as well.
Ferries link Shikoku to destinations including Kyūshū and islands around Shikoku.