The speed of Japan's modernization stunned the world. Within three years of the Meiji Restoration, the government dispatched the Iwakura Mission to circle the globe, studying American and European systems of law, education, industry, and military organization. They came home and dismantled feudalism with surgical precision. The caste system was formally abolished in 1869. An 1871 edict granted burakumin -- Japan's traditional untouchable class -- legal equality, though social discrimination persisted. The samurai lost their right to carry swords and wear the chonmage topknot. The government modeled its constitution after Prussia, its navy after Britain, and its universities after German research institutions. By 1890, Japan had an imperial constitution, a bicameral diet, and a modern conscript army. The country hired over 3,000 Western specialists to teach science, mathematics, and foreign languages. In barely a generation, Japan went from a closed feudal society to the only non-Western industrial power on Earth.

Japan's new military was not built for defense. The First Sino-Japanese War of 1894-1895 delivered Korea from Chinese suzerainty and gave Japan Taiwan and the Liaodong Peninsula -- though a humiliating Triple Intervention by Russia, Germany, and France forced Japan to return Liaodong. That insult was repaid a decade later when Japan stunned the world by defeating the Russian Empire in the Russo-Japanese War of 1904-1905, sinking the Russian Baltic Fleet at the Battle of Tsushima in one of the most decisive naval engagements in history. The Treaty of Portsmouth, negotiated by Theodore Roosevelt, gave Japan southern Sakhalin and confirmed its dominance in Korea, which was formally annexed in 1910. By 1931, Japan had invaded Manchuria, establishing the puppet state of Manchukuo under the last Manchu emperor, Puyi. Six years later, Japan invaded China proper. The fall of Nanjing in December 1937 produced one of the war's worst atrocities: the Nanjing Massacre, in which Japanese troops killed an estimated 200,000 to 300,000 people, many of them civilians.

Facing an American oil embargo and dwindling reserves, the Imperial Japanese Navy struck Pearl Harbor on December 7, 1941, killing nearly 2,500 Americans and crippling the U.S. Pacific Fleet. In the months that followed, Japan swept through Southeast Asia with staggering speed: Hong Kong fell on Christmas Day, Singapore surrendered on February 15, 1942 -- the largest capitulation of British-led forces in history, with 80,000 troops taken prisoner. The Philippines, the Dutch East Indies, Burma -- all fell in rapid succession. But the tide turned at Midway in June 1942, where Japan lost four fleet carriers in a single day, a blow from which the Imperial Navy never recovered. The American island-hopping campaign ground through Guadalcanal, the Philippines, Iwo Jima, and Okinawa. By early 1945, B-29 bombers were conducting devastating firebombing raids on Japanese cities. The March 9-10, 1945 raid on Tokyo alone killed approximately 120,000 civilians.

On August 6, 1945, an atomic bomb destroyed Hiroshima, killing an estimated 140,000 people by year's end. Three days later, a second bomb struck Nagasaki, killing 80,000. Between the two detonations, the Soviet Union declared war and invaded Manchuria, collapsing Japan's continental empire in days. On August 15, Emperor Showa addressed his subjects by radio for the first time in history, announcing Japan's surrender in language so formal that many listeners could barely understand it. The formal surrender ceremony took place aboard the USS Missouri in Tokyo Bay on September 2, 1945. General Douglas MacArthur oversaw the occupation that followed, imposing a new constitution that stripped the emperor of political power, renounced war in Article 9, and dissolved the empire entirely. Three emperors had reigned over Imperial Japan: Meiji, Taisho, and Showa. Showa would remain on the throne until 1989, a living link between the imperial past and democratic present.

MacArthur's occupation rebuilt Japan from the ground up. The feudal aristocracy was abolished, women gained the vote, labor unions were legalized, and a parliamentary democracy was established. When MacArthur sent all four occupation divisions to fight in Korea in 1950, he did so, he said, without the slightest qualm about the resulting power vacuum -- so thoroughly had Japan transformed. The Treaty of San Francisco, signed in 1951, formally ended the state of war and restored Japanese sovereignty. Japan's territory was reduced to the four main islands of Honshu, Hokkaido, Kyushu, and Shikoku. The corridors of power in postwar Japan, historian John Dower observed, were crowded with men whose talents had been recognized during the war years and who found those same talents prized in the new Japan. The empire was gone, but the energy that built it was redirected into an economic miracle that would make Japan the world's second-largest economy within a generation.