Japan is an East Asian island nation. It is located in the northwest Pacific Ocean, bounded on the west by the Sea of Japan, and stretches from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south. Japan is part of the Ring of Fire, with 6852 islands totalling 377,975 square kilometers (145,937 square miles); the five major islands are Hokkaido, Honshu (the "mainland"), Shikoku, Kyushu, and Okinawa. Tokyo is the nation's capital and biggest city, with Yokohama, Osaka, Nagoya, Sapporo, Fukuoka, Kobe, and Kyoto as prominent cities.
Japan is the world's tenth most populous nation, as well as one of its most densely inhabited and urbanized. Three-fourths of the country's topography is hilly, squeezing its 125.5 million people on narrow coastal plains. There are 47 administrative prefectures and eight traditional regions in Japan. With almost 37.4 million inhabitants, the Greater Tokyo Region is the world's most populated metropolitan area.
Japan has been inhabited since the Upper Paleolithic era (30,000 BC), but the earliest documented reference of the archipelago is in a Chinese chronicle (the Book of Han), which was completed in the second century AD. Between the fourth and ninth centuries, Japan's kingdoms were united under an emperor and the imperial court located in Heian-ky. Political authority was controlled by a succession of military dictators (shogun) and feudal lords (daimyo) beginning in the 12th century and enforced by a class of warrior nobles (samurai). Following a century of civil conflict, Japan was reunified in 1603 under the Tokugawa shogunate, which pursued an isolationist foreign policy. A US navy drove Japan to open commerce to the West in 1854, leading to the collapse of the shogunate and the restoration of imperial rule in 1868. During the Meiji era, the Empire of Japan adopted a Western-style constitution and embarked on an industrialization and modernization program. Japan invaded China in 1937 and joined World War II as an Axis power in 1941, amid a surge in militarism and foreign expansion. After defeat in the Pacific War and two atomic bombs, Japan surrendered in 1945 and was under Allied occupation for seven years, during which it established a new constitution and formed a military alliance with the United States. Japan has retained a unitary parliamentary constitutional monarchy with a bicameral legislature, the National Diet, under the 1947 constitution.
Japan is a major power and a member of various international organizations, including the United Nations (since 1956), the OECD, the Group of Twenty, and the Group of Seven. Despite having relinquished its ability to declare war, the government retains Self-Defense Forces that are among the world's most powerful. After WWII, Japan saw unprecedented growth in an economic miracle, becoming the world's second-largest economy by 1972, but has subsequently stagnated in what is known as the Lost Decades. The country's economy is the third-largest by nominal GDP and the fourth-largest by PPP as of 2021. Japan has one of the world's longest life expectancies, ranked "extremely high" on the Human Development Index, despite population reduction. Japan has made enormous contributions to science and technology as a worldwide leader in the automobile, robotics, and electronics sectors. Japan's culture, including its art, food, music, and popular culture, which includes strong comic, animation, and video game industries, is highly recognized across the globe.