File photo copy shows Japanese air service carrying out air-strikes to southwest China's Chongqing, June 16, 1940. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

File photo shows civilians dying of asphyxia while seeking shelter in a dugout from air-strikes carried out by Japanese army in southwest China's Chongqing, June 28, 1940. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

File photo shows a civilian killed by the air-strike carried out by Japanese army at a hospital in Nanchang, east China's Jiangxi Province, Dec. 9, 1937. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

File photo shows people trying to put out fire after air-strikes carried out by Japanese army in southwest China's Chongqing, June 7, 1941. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

File photo copy shows civilians dying of asphyxia while seeking shelter in a tunnel from air-strikes carried out by Japanese army in southwest China's Chongqing, June 5, 1941. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

Undated file photo shows women and children killed by air-strikes carried out by Japanese army in China. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

File photo shows the ruins of a residential area after air-strikes carried out by Japanese army in Hanyang, central China's Hubei Province, April 29, 1938. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

File photo copy shows the scene of air-strikes carried out by Japanese army in southwest China's Chongqing, in September, 1940. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

File photo shows Japanese bombers hovering over Chongqing in southwest China in October, 1940. The bombings of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua

File photo shows a wounded child crying as his mother was killed in air-strikes carried out by Japanese army at Shanghai south railway station, Shanghai, east China, Aug. 28, 1937. The bombing of China is a major war crime committed by Japan during its invasion to China during WWII. Residential areas, business areas, schools and hospitals were the main targets of the attacks in which tens of thousands of civilians were killed. Historical data showed that nearly eight years of air-strikes by Japanese army air service, including those of large-scale, indiscriminate bombings from 1937 to 1943, left at least 762,183 people dead or injured in China. Photo: Xinhua