In 1937, Japan invaded China and the resulting warfare laid waste to China. Most of the prosperous east China coast was occupied by the Japanese, who carried out various atrocities such as the Rape of Nanjing in 1937 and random massacres of whole villages. In one anti-guerrilla sweep in 1942, the Japanese killed up to 200,000 civilians in a month. The war was estimated to have killed between 20 and 25 million Chinese and destroyed all that Chiang had built up in the preceding decade. Development of industries was severely hampered after the war by devastating conflict as well as the inflow of cheap American goods. By 1946, Chinese industries operated at 20 percent capacity and had 25 percent of the output of pre-war China.