Honshu
, historically called , is the largest and most populous main island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island separates the Sea of Japan, which lies to its north and west, from the North Pacific Ocean to the south and east. It is the seventh-largest island in the world, and the second-most populous after the Indonesian island of Java. Honshu had a population of 104 million , constituting 81.3% of the entire population of Japan, and is mostly  concentrated in the coastal areas and plains. Approximately 30% of the total population resides in the Greater Tokyo Area on the Kantō Plain. As the historical center of Japanese cultural and political power, the island includes several past Japanese capitals, including Kyōto, Nara and Kamakura. Much of the island's southern shore forms part of the Taiheiyō Belt, a megalopolis that spans several of the Japanese islands. Honshu contains Japan's highest mountain, Mount Fuji, and its largest lake, Lake Biwa. Most of Japan's industry is located in a belt running along Honshu's southern coast, from Tokyo to  Nagoya, Kyōto, Osaka, Kobe, and Hiroshima; by contrast, the economy along the northwestern Sea of Japan coast is largely based on fishing and agriculture. The island is linked to the other three major Japanese islands by a number of bridges and tunnels. Its climate is humid and mild. Geography. The island is roughly long and ranges from wide, and its total area is , making it slightly larger than the island of Great Britain . Its land area has been increasing with land reclamation and coastal uplift in the north due to plate tectonics with a convergent boundary. Honshu has of coastline . Mountainous and volcanic, Honshu experiences frequent earthquakes (the Great Kantō earthquake heavily damaged Tokyo in September 1923, and the earthquake of March 2011 moved the northeastern part of the island by varying amounts of as much as while causing devastating tsunamis). The highest peak is the active volcano Mount Fuji at , which makes Honshu the world's 7th highest island. There are many rivers, including the Shinano River, Japan's longest. The Japanese Alps span the width of Honshu, from the 'Sea of Japan' coast to the Pacific shore. The climate is generally humid subtropical in western Japan and humid  continental in the north. Extreme points. Bridges and tunnels. Honshu is connected to the islands of Hokkaidō, Kyūshū and Shikoku by tunnels and bridges. Three bridge systems have been built across the islands of the Inland Sea between Honshu and Shikoku (Akashi Kaikyō Bridge and the Ōnaruto Bridge; Shin-Onomichi Bridge, Innoshima Bridge, Ikuchi Bridge, Tatara Bridge, Ōmishima Bridge, Hakata–Ōshima Bridge, and the Kurushima-Kaikyō Bridge; Shimotsui-Seto Bridge, Hitsuishijima Bridge, Iwakurojima Bridge, Yoshima Bridge, Kita Bisan-Seto Bridge, and the Minami Bisan-Seto Bridge), the Seikan Tunnel connects Honshu with Hokkaidō, and the Kanmonkyo Bridge and Kanmon Tunnel  connects Honshu with Kyūshū. Population. Honshu has a total population of 104 million people, according to a 2017 estimate, 81.3% of the entire population of Japan. The largest city is Tokyo (population: 37,339,804), the capital of Japan and part of the Greater Tokyo Area, the most populous metropolitan area in the world. Economy. Honshu island generates around US$4 trillion or 4/5 of Japan's GDP. Administrative regions and prefectures. The island is divided into five nominal regions and contains 34 prefectures, including metropolitan Tokyo. Administratively, some smaller islands are included within these prefectures, notably including the Ogasawara Islands, Sado  Island, Izu Ōshima, and Awaji Island. The regions and its prefectures are: Natural features. Agriculture. Fruit, vegetables, grains, rice and cotton make up the main produce grown in Honshu. The Tohoku region, spanning the north-eastern part of the island, is notable for its rice production, with 65% of cultivated land being rice paddy fields – almost a quarter of all paddy fields in Japan. Chiba Prefecture is famous for its peanuts, also being the largest producer in Japan. Rare species of the lichen genus Menegazzia are found only in Honshu. Industry. Most of Japan's tea and silk is from  Honshu. Minerals and fuels. Honshu is home to a large portion of Japan's minimal mineral reserves, also housing small deposits of oil and coal. Several coal deposits are also located in the northern part of the island, concentrated in Fukushima Prefecture and Niigata Prefecture, though Honshu's coal production is negligible in comparison to Hokkaido and Kyushu. Most of Japan's oil reserves are also located in northern Honshu, along the west coast, spanning Niigata, Yamagata and Akita Prefectures. In terms of mineral resources, Honshu houses the majority of Japan's copper, lead, zinc and chromite. Smaller deposits of  gold, silver, arsenic, sulphur and pyrite are also scattered across the island.