Pacific War

Japan's army occupied Manchuria in 1931 and full-scale war with China began in July 1937. The Chinese Nationalist and Communist forces were not defeated, and the war became a costly stalemate. Seeking raw materials, above all oil, and aiming to cut supply routes to China, Japan moved troops into northern French Indochina in 1940 and signed the Tripartite Pact with Germany and Italy. After Japanese forces entered southern Indochina in July 1941, the United States, Britain and the Netherlands froze Japanese assets and imposed an oil embargo.

Negotiations in Washington failed over the American demand that Japan withdraw from China. On 1 December 1941 an imperial conference approved war. Japanese carrier aircraft attacked the US Pacific Fleet at Pearl Harbor on the morning of 7 December, Hawaiian time (8 December in Japan), while other forces landed in British Malaya and attacked the Philippines, Guam and Hong Kong.

In the first six months Japan conquered Malaya and Singapore, which surrendered in February 1942, the Philippines, the Dutch East Indies, Burma and many Pacific islands. The tide turned in June 1942, when the US Navy sank four Japanese aircraft carriers at Midway, and during the long struggle for Guadalcanal (August 1942 – February 1943). American forces then advanced across the central and southwest Pacific, while British, Indian and Chinese forces fought in Burma and China.

The fall of Saipan in July 1944 brought the Japanese home islands within range of American bombers and led to Tōjō's resignation. At Leyte Gulf in October 1944 the Japanese navy was largely destroyed and the first organised suicide attacks by aircraft (tokkōtai, known abroad as kamikaze) were launched. Iwo Jima fell in March 1945.

Japanese rule in the occupied territories was harsh. Although some nationalist leaders initially cooperated in the hope of independence from Western colonial powers, occupation brought requisitioning, forced labour and violent repression. Hundreds of thousands of Asian labourers and tens of thousands of Allied prisoners were forced to build the Burma–Thailand Railway, where many thousands died. Prisoners of war held by Japan died at far higher rates than those held by Germany in the West. Massacres of civilians occurred in China, Singapore, the Philippines and elsewhere, and in China Unit 731 conducted biological warfare research and experiments on prisoners.

Women from Korea, China, the Philippines, Indonesia, the Netherlands and other countries were forced into military brothels euphemistically called 'comfort stations'. The number of these 'comfort women' and the extent of coercion have been debated, but the Japanese government acknowledged in the Kōno Statement of 1993 that the military was directly or indirectly involved and that many women were recruited against their will. Koreans and Chinese were also mobilised for labour in Japanese mines and factories. These issues remain central to Japan's relations with its neighbours.

Inside Japan the war meant total mobilisation. Food and goods were rationed, students were sent to work in factories, women were mobilised for labour, and from 1944 schoolchildren were evacuated from the cities. Censorship and the police suppressed dissent. From late 1944 American B-29 bombers attacked Japanese cities with incendiary bombs. The raid on Tokyo on the night of 9–10 March 1945 killed around 100,000 people, and more than sixty cities were largely burned out.

From 1 April to late June 1945 American forces fought to take Okinawa, the only major land battle on Japanese home territory. More than 200,000 people died, including about 94,000 Okinawan civilians and many Okinawans conscripted into Japanese units – roughly a quarter of the prefecture's population. Civilians were caught between the armies, sheltered in caves, and in some places died in mass suicides; the role of the Japanese military in these deaths has been the subject of court cases and textbook disputes. Okinawa Memorial Day on 23 June commemorates the end of organised fighting; the Cornerstone of Peace in Itoman lists the names of all who died, regardless of nationality.

On 26 July 1945 the Allies issued the Potsdam Declaration demanding Japan's unconditional surrender. The Japanese government did not accept it. On 6 August at 8:15 a.m. an American B-29 dropped an atomic bomb on Hiroshima; on 9 August at 11:02 a.m. a second bomb destroyed much of Nagasaki. By the end of 1945 an estimated 140,000 people had died in Hiroshima and around 74,000 in Nagasaki, many of them from burns and radiation; survivors (hibakusha), including many Korean residents, suffered lasting illness and discrimination. On 9 August the Soviet Union declared war and invaded Manchuria.

At an imperial conference in the night of 9–10 August, with the cabinet deadlocked, Emperor Shōwa supported acceptance of the Potsdam terms. His recorded broadcast announcing the end of the war was aired on 15 August 1945. The instrument of surrender was signed on the USS Missouri in Tokyo Bay on 2 September. Whether the atomic bombings were necessary to end the war, and the relative weight of the bombs and the Soviet entry in Japan's decision, remain subjects of historical debate.

Japan's war dead numbered about 3.1 million, including some 800,000 civilians. China's losses in the war from 1937 are estimated in the tens of millions of dead and wounded, and millions more died elsewhere in Asia. After the surrender more than six million Japanese soldiers and civilians were repatriated from overseas, while hundreds of thousands were detained in Soviet labour camps, where tens of thousands died. The Tokyo Tribunal and other Allied courts tried Japanese leaders and thousands of lower-ranking defendants for war crimes.

Remembrance remains contested. The national memorial service for the war dead is held on 15 August, attended by the emperor. Official statements, notably the Murayama Statement of 1995, have expressed remorse and apology for colonial rule and aggression, while visits by politicians to Yasukuni Shrine, textbook content and the issues of 'comfort women' and forced labour continue to strain relations with China and the Koreas. Hiroshima and Nagasaki have made remembrance of the bombings a global call for the abolition of nuclear weapons.