Casualties and war crimes

Estimates for the total casualties of the war vary, but most suggest that some 60 million people died in the war, including about 20 million soldiers and 40 million civilians.[195][196][197] Many civilians died because of disease, starvation, massacres, bombing and deliberate genocide. The Soviet Union lost around 27 million people during the war, about half of all World War II casualties.[198] Of the total deaths in World War II, approximately 85 percent were on the Allied side (mostly Soviet and Chinese) and 15 percent on the Axis side. One estimate is that 12 million civilians died in Nazi concentration camps,[199] 1.5 million by bombs, 7 million in Europe from other causes, and 7.5 million in China from other causes.[200] Figures on the amount of total casualties vary to a wide extent because the majority of deaths were not documented.

Many of these deaths were a result of genocidal actions committed in Axis-occupied territories and other war crimes committed by German as well as Japanese forces. The most notorious of German atrocities was The Holocaust, the systematic genocide of Jews in territories controlled by Germany and its allies. The Nazis also targeted other groups, including the Roma (targeted in the Porajmos), Slavs, and gay men, exterminating an estimated five million additional people.[201] The targets of the Axis-aligned Croatian Ustaše regime were mostly Serbs.[202] The best-known Japanese atrocity is the Nanking Massacre, in which several hundred thousand Chinese civilians were raped and murdered.[203] The Japanese military murdered from nearly 3 million to over 10 million civilians, mostly Chinese.[204] According to Mitsuyoshi Himeta, at least 2.7 million died during the Sankō Sakusen implemented in Heipei and Shantung by General Yasuji Okamura.

Limited Axis usage of biological and chemical weapons is also known. The Italians used mustard gas during their conquest of Abyssinia,[205] while the Japanese Imperial Army used a variety of such weapons during their invasion and occupation of China (see Unit 731)[206][207] and in early conflicts against the Soviets.[208] Both the Germans and Japanese tested such weapons against civilians[209] and, in some cases, on prisoners of war.[210]

While many of the Axis's acts were brought to trial in the world's first international tribunals,[211] incidents caused by the Allies were not. Examples of such Allied actions include population transfer in the Soviet Union,[212] the Soviet forced labour camps (Gulag),[213] Japanese American internment in the United States, the Operation Keelhaul,[214] expulsion of Germans after World War II, the Soviet massacre of Polish citizens and the mass-bombing of civilian areas in enemy territory, including Tokyo and most notably at Dresden.[215]

Large numbers of deaths can also be attributed, if even partially, indirectly to the war, such as the Bengal famine of 1943.