Japan

is an island nation located on the Pacific Ocean, east of China and Korea, stretching from the Sea of Okhotsk in the north to the East China Sea in the south. It is composed of over 3,000 islands, the largest of which are Hokkaidô, Honshû, Shikoku, and Kyûshû. Most of Japan's islands are mountainous, and many are volcanic; the highest peak is Mount Fuji. Japan is the world's second-largest economy after the U.S. and one of the world's leading industrialized countries. It is a unitary constitutional monarchy with an emperor and an elected parliament, one of the oldest legislatures in Asia. Despite its rugged terrain, it is one of the most populous—and one of the most densely populated—countries in the world. Its capital Tokyo, with over 30 million residents, is the largest metropolitan area in the world.