Showa period

The early Shōwa years were marked by the financial crisis of 1927 and the world depression, which hit Japanese farmers hard through the collapse of silk and rice prices. Radical nationalists and young officers blamed party politicians and business for the country's distress. In September 1931 officers of the Kwantung Army staged a railway explosion near Mukden as a pretext to occupy Manchuria, and in 1932 the puppet state of Manchukuo was proclaimed. The same year naval officers assassinated Prime Minister Inukai Tsuyoshi, ending party cabinets. Japan left the League of Nations in 1933 after it refused to recognise Manchukuo.

An attempted coup by army officers on 26 February 1936 failed but increased the military's political weight. Japan signed the Anti-Comintern Pact with Germany in 1936 and the Tripartite Pact with Germany and Italy in 1940. From 1938 the National Mobilisation Law placed the economy under state control, and in 1940 the political parties dissolved into the Imperial Rule Assistance Association.

A clash near the Marco Polo Bridge outside Beijing in July 1937 escalated into full-scale war with China. Japanese forces took Shanghai and the capital Nanjing, where troops killed large numbers of prisoners and civilians over several weeks from December 1937; the scale of the Nanjing Massacre is disputed, but the atrocities are established by extensive evidence and were acknowledged by the Japanese government. The war became a long stalemate. Seeking the resources of Southeast Asia, Japan moved into French Indochina, and after the United States, Britain and the Netherlands imposed an oil embargo, it attacked Pearl Harbor and British and American territories across the Pacific on 7–8 December 1941.

After rapid early conquests, Japan's advance was halted at Midway in 1942. The war that followed brought immense suffering to the occupied countries of Asia, including forced labour and the system of military 'comfort stations' in which women, many of them from Korea, were forced to serve Japanese soldiers. From 1944 American bombing destroyed most Japanese cities; the Battle of Okinawa in 1945 killed a large part of the island's population. After the atomic bombings of Hiroshima on 6 August and Nagasaki on 9 August and the Soviet declaration of war, Emperor Shōwa announced Japan's surrender in a radio broadcast on 15 August 1945. The instrument of surrender was signed on 2 September.

From 1945 to 1952 Japan was occupied by Allied forces under the Supreme Commander, General Douglas MacArthur, with the Japanese government ruling under its direction. The occupation disbanded the military, purged wartime leaders, abolished State Shinto, dissolved the zaibatsu, carried out a sweeping land reform that turned tenants into owners, legalised labour unions and gave women the vote. In January 1946 the emperor publicly rejected the idea of his own divinity. The International Military Tribunal for the Far East (1946–1948) tried wartime leaders; seven, including former prime minister Tōjō Hideki, were executed.

The Constitution of Japan, drafted largely by occupation staff and debated and amended by the Diet, was promulgated on 3 November 1946 and took effect on 3 May 1947. It made the people sovereign and the emperor 'the symbol of the State', guaranteed fundamental rights, and in Article 9 renounced war and the maintenance of armed forces for that purpose – an article whose interpretation, particularly regarding the Self-Defence Forces established in 1954, has remained a central political debate. The San Francisco Peace Treaty, effective on 28 April 1952, ended the occupation; the Japan–US Security Treaty, signed alongside it in 1951, kept American bases in Japan. Okinawa remained under US administration until 1972.

After the hardship of the immediate postwar years, the Korean War of 1950–1953 brought American procurement orders that revived industry. From the mid-1950s to the early 1970s the economy grew at roughly ten per cent a year, driven by high savings and investment, new technology, a well-educated workforce, industrial policy and access to world markets. Prime Minister Ikeda Hayato's Income Doubling Plan of 1960 captured the mood. Households acquired the 'three sacred treasures' – television, washing machine and refrigerator – and later cars, colour televisions and air conditioners.

The oil shock of 1973 ended high-speed growth, but Japanese firms in cars, electronics and steel adapted and conquered world markets. Rapid industrialisation also caused severe pollution diseases, such as Minamata disease from mercury poisoning, which led to strict environmental laws from 1970. After the Plaza Accord of 1985 the rising yen and loose monetary policy fed an asset bubble in stocks and land that was at its peak when the era ended.

In 1955 the conservative parties merged into the Liberal Democratic Party (LDP), which held power without interruption for the rest of the era, facing a socialist opposition – the so-called 1955 system. The revision of the security treaty in 1960 provoked the largest protests in Japanese history. Japan joined the United Nations in 1956, normalised relations with South Korea in 1965 and with the People's Republic of China in 1972.

Society changed profoundly. Millions moved from the countryside to the cities, the nuclear family and the white-collar 'salaryman' became the norm, and university enrolment soared. The Tokyo Olympics of 1964 and the Osaka Expo of 1970 symbolised Japan's return to the international community. Student protests peaked in the late 1960s, and the 1970s and 1980s brought growing affluence, consumer culture and concern about an ageing society.

Until 1945 State Shinto and emperor worship were promoted in schools and public life, and religious groups that deviated from official orthodoxy, such as Ōmoto and the precursor of Sōka Gakkai, were suppressed. The occupation's Shinto Directive of December 1945 ended state support for shrines, and the 1947 constitution separated religion and state. The postwar decades saw the rapid growth of new religious movements, above all Sōka Gakkai, whose political party Kōmeitō was founded in 1964. Visits by prime ministers to Yasukuni Shrine, where convicted war criminals were enshrined in 1978, became a recurring source of domestic and international controversy.

Wartime culture was subject to censorship and propaganda, but the postwar decades were exceptionally creative. Kurosawa Akira's Rashōmon won the top prize at the Venice Film Festival in 1951 and introduced Japanese cinema to the world, alongside Ozu Yasujirō and Mizoguchi Kenji. Godzilla (1954) turned nuclear fear into a monster film. Tezuka Osamu shaped modern manga and television anime, from Astro Boy onwards. Kawabata Yasunari received the Nobel Prize in Literature in 1968, while Mishima Yukio's writing and his suicide in 1970 embodied the tensions of postwar identity. Architects such as Tange Kenzō created a modern Japanese architecture, and consumer electronics such as the Sony Walkman (1979) made Japanese design global.

Shōwa is remembered in Japan in two very different ways: as a time of militarism, war and catastrophe, and as the age of recovery, growth and rising living standards. Both memories shape the present. The constitution of 1947 remains unamended, the US–Japan alliance continues, and questions of war responsibility – textbooks, the 'comfort women' issue, forced labour and Yasukuni – remain part of Japan's relations with China and the Koreas. Hiroshima and Nagasaki have made Japan a leading voice for nuclear disarmament.

Emperor Shōwa died on 7 January 1989. His birthday, 29 April, is observed as Shōwa Day, a national holiday intended as an occasion to reflect on the turbulent era.