Japan, with a population of more than 127 million (2016), consists of four major islands, Hokkaido, Honshu (the main island), Shikoku and Kyushu, and about 6,800 small islands. These islands form an arc off the coast of northeast Asia, extending from latitude 45°north to latitude 20°north. They are approximately 3,000km in length and cover an area of 377,880㎢. About 68% of this area is classed as mountainous, and only about 13% of the area is under cultivation. The northern coast of Honshu is about 960km off the coast of Siberia, and the distance between the west coast of Kyushu and shanghai in China approximately 850km. The Tsushima Strait separating Japan from Korea measures about 200km in width, and this proximity permitted the easy flow of Chinese and Korean culture to Japan in historical times.