In 1854, U.S. Commodore Matthew Perry forced the opening of Japan to the West with the Convention of Kanagawa. The perceived weakness of the shogunate led many samurai to revolt, leading to the Boshin War of 1867-8. Subsequently the shogunate resigned and the Meiji Restoration returned the Emperor to power. Japan adopted numerous Western institutions in the Meiji period, including a modern government, legal system, and military. These reforms transformed the Empire of Japan into a world power that defeated China in the Sino-Japanese War and Russia in the Russo-Japanese War. By 1910, Japan controlled Taiwan, half of Sakhalin, and Korea.


The early 20th century saw a brief period of "Taisho democracy" overshadowed by the rise of Japanese expansionism. In 1936, Japan signed the Anti-Comintern Pact and joined with Germany and Italy to form the axis alliance. In 1937, Japan invaded Manchuria that led to the second Sino-Japanese War (1937). In 1941, Japan attacked the United States naval base in Pearl Harbor, bringing America into World War II. After a long campaign in the Pacific Ocean, Japan lost its initial territorial gains, and the United States moved into range to begin strategic bombing of Tokyo, Osaka and other major cities as well as atomic bombing at Hiroshima and Nagasaki. Japan eventually agreed to an unconditional surrender to the Allies on August 15, 1945 (V-J Day).


Official American occupation lasted until 1952, although U.S. forces still retain important bases in Japan, especially in Okinawa. Japan adopted a new constitution, establishing the country as a pacifist democratic nation, in 1947 under the occupation authority. After occupation, under a program of aggressive industrial development, protectionism, and deferral of strategic defense to the United States, Japan's gross national product rose to build one of the largest economies in the world. Despite a major stock market crash in 1990, from which the country has not fully recovered, Japan remains a global economic power and has recently begun to re-emerge as a strategic power, lending non-combat support to the Gulf War, the UN efforts to rebuild Cambodia, and the 2003 invasion of Iraq.