World War II

World War II was a global conflict fought mainly between two coalitions. The Axis powers—Germany, Italy and Japan, joined by smaller allies—set out to conquer territory and build empires. The Allies—above all the Soviet Union, the United States, the British Empire and Commonwealth, and China, together with many other states and resistance movements—fought to stop them.

The usual dates in Europe are 1939 to 1945, from Germany's invasion of Poland to Japan's surrender. But in East Asia many historians begin the war earlier: Japan seized Manchuria in 1931, and full-scale war between Japan and China began in July 1937. For China, the war lasted eight years, or fourteen if counted from 1931. For the Soviet Union, the central experience was the war with Germany from 1941 to 1945, which Russians call the Great Patriotic War.

It was the largest and deadliest war in human history. Estimates of the dead range from about 60 to 75 million people, most of them civilians. It included genocide, the mass bombing of cities, the forced movement and enslavement of millions of workers, famine, and the first and only use of nuclear weapons in war.

The First World War and its peace settlement left deep resentment, especially in Germany. The Great Depression that began in 1929 caused mass unemployment and helped extremist movements win support. In Italy, Benito Mussolini's Fascists had taken power in 1922. In Germany, Adolf Hitler and the Nazi Party came to power in 1933 with a programme of racial nationalism, antisemitism, rearmament and conquest of 'living space' (Lebensraum) in Eastern Europe.

In Japan, the military gained growing influence over politics. Japan had already made Taiwan (1895) and Korea (annexed 1910) into colonies. In 1931 the Japanese army seized Manchuria and set up a puppet state, Manchukuo. In July 1937 a clash near Beijing at the Marco Polo Bridge grew into full-scale war with China. Japanese forces captured Nanjing in December 1937 and carried out mass killings and rapes; estimates of the victims of the Nanjing Massacre vary widely and remain politically contested, with many historians citing figures in the tens of thousands to around 200,000 or more, and the official Chinese figure 300,000.

In Europe, Germany rearmed, remilitarised the Rhineland (1936), annexed Austria (March 1938) and, with the agreement of Britain and France at Munich, took the Sudetenland from Czechoslovakia (September 1938). Britain and France followed a policy of 'appeasement', hoping to avoid another war. In March 1939 Germany occupied the rest of the Czech lands. In August 1939 Germany and the Soviet Union signed a non-aggression pact (the Molotov–Ribbentrop Pact), with a secret protocol dividing Eastern Europe between them. On 1 September Germany invaded Poland, and on 3 September Britain and France declared war.

Poland was defeated within weeks, attacked from the west by Germany and from the east by the Soviet Union on 17 September. Both occupiers treated Poles brutally: the Germans killed members of the Polish elite and began persecuting Jews, and the Soviets deported hundreds of thousands and murdered some 22,000 Polish officers and others at Katyn and elsewhere in 1940.

In spring 1940 Germany conquered Denmark and Norway, then the Netherlands, Belgium, Luxembourg and France in about six weeks. British and French troops were evacuated from Dunkirk. France signed an armistice; the north was occupied, and a collaborationist regime ruled from Vichy, while Charles de Gaulle led the 'Free French' from London. Britain, under Prime Minister Winston Churchill, fought on alone in Europe and resisted German air attacks in the Battle of Britain.

Italy entered the war in June 1940 and fought in North Africa and the Balkans, often needing German help. In 1941 Germany conquered Yugoslavia and Greece. Across occupied Europe, resistance movements formed, while other people collaborated with the occupiers; the balance between resistance, collaboration and survival remains a sensitive subject in many countries.

On 22 June 1941 Germany and its allies invaded the Soviet Union in Operation Barbarossa, the largest invasion in history. The war in the East was planned from the start as a war of annihilation. German armies advanced to the gates of Leningrad and Moscow. Leningrad was besieged for almost 900 days, and around a million or more of its civilians died, mostly of starvation. Millions of Soviet prisoners of war—around three million by most estimates—died of hunger, disease and execution in German captivity.

The Red Army stopped the Germans before Moscow in December 1941. The Battle of Stalingrad (1942–1943), which ended with the surrender of a German army, is widely seen as a turning point. After the German defeat at Kursk in 1943, the Soviet forces advanced westward, and the destruction of German Army Group Centre in Operation Bagration in 1944 opened the way to Poland and Germany. The Red Army captured Berlin in late April and early May 1945.

The Eastern Front accounted for the majority of German military losses. The Soviet Union's deaths, estimated at 20–27 million, were the highest of any country. Belarus, Ukraine, the Baltic states and western Russia suffered occupation, mass shootings, burned villages and famine. The Soviet regime also committed its own violence during the war, including the deportation of entire peoples, such as Chechens and Crimean Tatars, accused of disloyalty.

The Holocaust was the systematic, state-organised persecution and murder of about six million European Jews by Nazi Germany and its allies and collaborators between 1941 and 1945, following years of discrimination and violence after 1933. Jews were stripped of rights and property, forced into ghettos, and then murdered: by mass shootings in the occupied Soviet territories, carried out by the Einsatzgruppen and other units with local helpers, and in killing centres in occupied Poland such as Auschwitz-Birkenau, Treblinka, Sobibor, Bełżec, Chełmno and Majdanek, where victims were gassed.

Roma and Sinti were also targeted for extermination; estimates of Roma victims vary greatly, from around 200,000 to 500,000. Before and during the war the Nazis murdered around a quarter of a million disabled people in 'euthanasia' programmes. Polish civilians, Soviet prisoners of war, political opponents, homosexual men, Jehovah's Witnesses and others were persecuted and killed. Millions of people from occupied Europe were deported to Germany as forced labourers.

The Holocaust is documented by an enormous body of evidence: German administrative records, the testimony of survivors, perpetrators and bystanders, photographs, and the physical remains of camps. Survivor testimony, such as the diary of Anne Frank written in hiding in Amsterdam, and the later memoirs of Primo Levi and Elie Wiesel, have shaped how the world understands it. Jewish resistance included the Warsaw Ghetto Uprising of 1943 and revolts at Treblinka and Sobibor.

China bore the longest struggle. Nationalist forces under Chiang Kai-shek and Communist forces under Mao Zedong both fought Japan, while also competing with each other. Chinese armies tied down large numbers of Japanese troops for eight years. Japanese forces carried out massacres, the 'Three Alls' anti-guerrilla campaigns in north China, bombing of cities such as Chongqing, and biological and chemical warfare, including experiments on human beings by Unit 731 in Manchuria. China's dead are estimated at 14–20 million, with tens of millions more made refugees.

Seeking oil and raw materials, and facing an American embargo, Japan attacked the US fleet at Pearl Harbor on 7 December 1941 and simultaneously struck British Malaya, Hong Kong and the Philippines. Within months Japan conquered Southeast Asia, including Singapore, the Dutch East Indies (today's Indonesia) and Burma, presenting itself as the liberator of Asia under the slogan of a 'Greater East Asia Co-Prosperity Sphere'. In practice occupation brought forced labour, requisitioning of food and brutal repression. Allied prisoners of war and hundreds of thousands of Asian labourers ('rōmusha') were forced to build the Burma–Thailand railway; famines struck Vietnam in 1944–45 and Bengal in 1943 under British rule, where wartime policies worsened the disaster.

The tide turned at the naval Battle of Midway (June 1942) and at Guadalcanal (1942–43). American forces advanced across the Pacific in 'island-hopping' campaigns, while British and Indian forces fought in Burma. The battles of Iwo Jima and Okinawa in 1945 were extremely bloody; many Okinawan civilians died, some forced or pressured into mass suicides. American bombers destroyed Japanese cities with incendiary raids; the firebombing of Tokyo in March 1945 killed around 100,000 people in one night. On 6 and 9 August 1945 the United States dropped atomic bombs on Hiroshima and Nagasaki, killing an estimated 150,000–246,000 people by the end of 1945, and on 8 August the Soviet Union declared war on Japan and invaded Manchuria. Japan announced its surrender on 15 August and signed it on 2 September 1945.

Korea did not fight as an independent state, because it had been a Japanese colony since 1910. After 1937, the colonial government pursued a policy of forced assimilation: Koreans were required to worship at Shinto shrines, recite an oath of loyalty to the emperor, use Japanese in schools and, from 1940, adopt Japanese-style names (sōshi-kaimei). The National Mobilization Law of 1938 was applied to Korea, allowing the state to direct labour and resources for the war.

Large numbers of Koreans were mobilised for labour in mines, factories, construction sites and military facilities in Korea, Japan, Sakhalin, Manchuria and the Pacific islands. Recruitment moved from nominally voluntary 'recruitment' (from 1939) through 'government-arranged' placement (from 1942) to formal conscription under the National Requisition Ordinance (applied to Koreans from 1944); in practice coercion was common in all stages. Estimates of those mobilised vary greatly depending on what is counted: a figure of around 5.4 million mobilisations, including repeated and domestic mobilisation, is often cited, while estimates of those taken outside Korea for labour are commonly in the hundreds of thousands. Many worked in dangerous conditions for little or withheld pay, and some died. Koreans were also recruited as soldiers—first as 'volunteers' from 1938, then by conscription from 1944—and as military civilian employees, including prison-camp guards, some of whom were later tried as war criminals by the Allies.

The Japanese military also established a system of 'comfort stations' across its empire, in which women and girls were held for sexual use by soldiers. Victims came from Korea, China, Taiwan, the Philippines, Indonesia, the Netherlands and elsewhere; Korean women were among the largest groups. Estimates of the total number range widely, commonly from about 20,000 to 200,000, and some scholars suggest higher figures. Many were deceived with promises of work or taken by force, and survivors described systematic rape and abuse. The issue became public in 1991 when Kim Hak-sun gave testimony. In the 1993 Kōno Statement the Japanese government acknowledged the military's involvement and coercion and apologised; a 2015 South Korea–Japan agreement set up a fund of one billion yen, but it was rejected by many survivors and supporters and remains disputed. Some Japanese politicians and writers deny coercion, while survivors, UN human rights bodies and most historians describe the system as sexual slavery.

Tens of thousands of Koreans were among the victims of the atomic bombings of Hiroshima and Nagasaki, many of them labourers. Korean independence activists fought on: the Korean Provisional Government in China declared war on Japan in December 1941, and its Korean Liberation Army was formed in 1940; other Korean fighters operated in Manchuria and with Chinese Communist forces. Japan's surrender on 15 August 1945 brought liberation (Gwangbok), but the peninsula was immediately divided at the 38th parallel into Soviet and American occupation zones, the starting point of the division of Korea.

In the Atlantic, German submarines tried to cut Britain's supply lines; Allied convoys, code-breaking (including the work at Bletchley Park on the Enigma cipher) and air patrols gradually won this battle by 1943. The United States supplied Britain, the Soviet Union and China with vast amounts of equipment through Lend-Lease. In North Africa, British and Commonwealth forces defeated German and Italian armies at El Alamein in 1942, and Anglo-American forces landed in Morocco and Algeria.

The Allies invaded Sicily and Italy in 1943; Mussolini was deposed, and Italy surrendered but was then occupied by Germany, leading to a long campaign and an Italian civil war between the Resistance and the fascist Salò Republic. On 6 June 1944 (D-Day) Allied armies landed in Normandy, liberating Paris in August. British and American bombers attacked German cities throughout the war; raids on Hamburg (1943) and Dresden (1945) killed tens of thousands of civilians in single operations, and the morality and effectiveness of area bombing remain debated.

Germany's last offensive, in the Ardennes (the Battle of the Bulge, December 1944), failed. As Allied armies entered Germany from east and west, they liberated concentration camps and revealed the full horror of Nazi crimes. Hitler killed himself in Berlin on 30 April 1945, and Germany surrendered unconditionally on 7–8 May 1945.

Estimates of the dead are uncertain but enormous: about 60–75 million, including deaths from war-related famine and disease. Civilians made up more than half. The Soviet Union and China together account for more than half of all deaths; Poland lost around 17 percent of its pre-war population, including about three million Polish Jews. Germany's dead are estimated at about 7 million and Japan's at 2.5–3.1 million. Figures for Southeast Asia, India, Korea and other colonies are particularly uncertain.

The war left tens of millions of refugees and displaced people. Between 1944 and 1950 some 12 million or more ethnic Germans fled or were expelled from Eastern Europe; millions of Japanese soldiers and settlers were repatriated from the former empire, and many Koreans returned home from Japan, while others remained in Japan or were stranded in Sakhalin. Germany and Japan were occupied, and the Nuremberg and Tokyo tribunals tried leading officials for crimes against peace, war crimes and crimes against humanity.

The war reshaped the world order. The United States and the Soviet Union emerged as superpowers, and their rivalry soon became the Cold War, which divided Germany and Korea. The United Nations was founded in 1945, the Universal Declaration of Human Rights adopted in 1948 and the Genocide Convention the same year. The European colonial empires, weakened and discredited, began to dissolve, with independence for India, Indonesia, the Philippines, Vietnam and many others in the following decades.

Memory of the war differs sharply between countries. In Germany, after early silence and resistance, a long process of 'coming to terms with the past' (Vergangenheitsbewältigung) made acknowledgment of Nazi crimes and the Holocaust central to public culture, marked by memorials such as the Memorial to the Murdered Jews of Europe in Berlin. In Russia, victory in the Great Patriotic War is a central pillar of national identity, celebrated on 9 May; the Molotov–Ribbentrop Pact and Soviet crimes are sensitive subjects. In Britain and the United States the war is often remembered as a 'good war' against evil, though historians have questioned the bombing of cities and the atomic bombings.

In Japan, memory has been divided. Hiroshima and Nagasaki are central to a strong pacifist tradition, and many Japanese remember themselves chiefly as victims of the war. At the same time there have been prolonged disputes over school textbooks, the Yasukuni Shrine (where convicted war criminals are among the enshrined war dead), the Nanjing Massacre, forced labour and the 'comfort women'. Official apologies, such as the 1995 statement of Prime Minister Murayama Tomiichi, coexist with statements by politicians that minimise Japanese responsibility.

In China, the War of Resistance against Japan is central to national memory; the emphasis given to Nationalist and Communist roles has changed over time. In South Korea, the war is remembered above all through the colonial experience: forced mobilisation, the 'comfort women', and the independence movement, commemorated on Liberation Day (15 August). Lawsuits by former forced labourers, including a 2018 South Korean Supreme Court ruling ordering Japanese companies to pay compensation, conflict with Japan's position that claims were settled by the 1965 treaty normalising relations, and have repeatedly strained relations. Weekly protests in Seoul since 1992 and 'Statue of Peace' memorials keep the 'comfort women' issue in public view. In Southeast Asia, India and Africa, memory focuses on colonial soldiers, famine and the road to independence.

Sources for the war are vast: government and military archives, captured German records used at Nuremberg, diaries, letters, photographs, film, and the testimony of survivors. Much was also destroyed; Japanese authorities burned many documents in August 1945, which complicates research on topics such as the 'comfort women' and forced labour and has made survivor testimony and scattered surviving documents especially important. The opening of Soviet archives after 1991 transformed research on the Eastern Front and on Soviet repression.

Historians have debated the origins of the war—for example A. J. P. Taylor's controversial argument in 1961 that Hitler was an opportunist rather than a planner, against the majority view stressing Hitler's ideological goals. Holocaust historiography has moved from Raul Hilberg's study of the bureaucratic machinery of destruction to debates between 'intentionalists' and 'functionalists' over whether the genocide followed a long-held plan or radicalised step by step, and to closer study of local perpetrators, victims' experiences and collaboration across Europe.

Global histories, such as Gerhard Weinberg's A World at Arms (1994), have insisted on treating all theatres together. Work by Rana Mitter and others has recovered China's central role, long neglected in Western accounts. Scholars also debate the decision to use the atomic bombs, the role of Lend-Lease and the Soviet contribution to victory, and how to integrate colonial and non-European experiences, including those of Koreans, Indians, Africans and Southeast Asians, into a history once told mainly from the perspective of the great powers.