In July 1937, Japanese forces launched a pre-emptive, full-scale invasion of China, sparking the Second Sino-Japanese War. The Japanese Army advanced rapidly into the heart of Chinese territory. By June 1938, the Japanese had taken control of all of North China. They also easily captured the coastal cities of China’s eastern provinces. The Nationalist strongholds of Shanghai, Nanjing, and Wuhan also fell.
To stop the Japanese from advancing into western and southern China, Nationalist leader Chiang Kai-shek ordered that the dikes of the Yellow River be destroyed. On June 5-7, 1938, the dikes on the south bank were demolished, and flood waters spilled into and destroyed vast stretches of farmlands in Henan, Anhui, and Jiangsu, . In the aftermath, the Nationalist government estimated that 800,000 people were killed while 10 million lost their homes. A 1994 study by the Red Chinese government placed the figures at 900,000 killed and 10 million displaced. Data from more recent studies put the estimate at 400,000-500,000 dead and 3-5 million displaced. The difficulty with ascertaining exact figures is that at the time of the flooding, local officials had already fled from the areas, leaving no government control. Because of the sheer numbers of deaths and displaced and the extensive destruction generated, the 1938 Yellow River Flood is regarded as the “largest act of environmental warfare in history”.
(taken from Wars of the 20th Century – Volume 1)
Chiang Kai-shek Chiang committed major military blunders. At Nanjing, for instance, he allowed his forces to be trapped and destroyed. Consequently, the Japanese killed 200,000 civilians and soldiers in the city. Then in a scorched earth strategy to delay the enemy’s advance, Chiang ordered the dams destroyed around Nanjing, which caused the Yellow River to flood and kill hundreds of thousands of people. Furthermore, as the Nationalist forces retreated westward, they set fire to Changsha to prevent the city’s capture by the Japanese, but this resulted in the deaths of 20,000 residents and the displacement of hundreds of thousands more, who were not told of the plan.
The Chinese people’s confidence in their government plummeted, as it seemed to them that the Nationalist Army was incapable of saving the country. At the same time, the Communists’ popularity soared because, unlike the Nationalists who used costly open warfare against the Japanese, the Red Army employed guerilla tactics with great success against the mostly lightly defended enemy outposts in remote areas.