Island (pop., 2004 est.: 103,152,000), Japan. The largest of the four main islands of Japan, its coastline extends 6,266 mi (10,084 km); it has an area of 88,012 sq mi (227,950 sq km). It is regarded as the Japanese mainland, and much of the country's early history took place in its southwestern region. Honshu's Pacific coast is the country's main economic centre, lined with the metropolitan areas of Tokyo-Yokohama, Nagoya, and Osaka-Kobe. Honshu contains Japan's tallest mountain, Mount Fuji, and its largest lake, Lake Biwa.