The 1938 Yellow River flood (, literally "Huayuankou embankment breach incident") was a flood created by the Nationalist Government in central China during the early stage of the Second Sino-Japanese War in an attempt to halt the rapid advance of Japanese forces. It has been called the "largest act of environmental warfare in history" and an example of scorched earth military strategy. Strategic decision and subsequent flood Following the onset of the Second Sino-Japanese War in 1937, the Imperial Japanese Army marched rapidly into the heart of Chinese territory. By June 1938, the Japanese had control of all of North China. On June 6, they captured Kaifeng, the capital of Henan, and threatened to take over Zhengzhou, the junction of the arterial Pinghan and Longhai Railways. Japanese success here would have directly endangered the major city of Wuhan. To stop further Japanese advances into western and southern China, Chiang Kai-shek, at the suggestion of Chen Guofu, determined to open up the dikes (levees) on the Yellow River near Zhengzhou. The original plan was to destroy the dike of Zhaokou, but due to difficulties at that location, the dike of Huayuankou, on the Yellow River's south bank, was destroyed on June 5 and June 7 via tunneling, with waters flooding into Henan, Anhui, and Jiangsu. The floods covered and destroyed thousands of square kilometers of farmland, and shifted the course of the Yellow River hundreds of kilometers to the south. Thousands of villages were inundated, and several million villagers were forced from their homes and made refugees. An unknown number of Japanese soldiers were killed by the flood. An official Kuomintang-led postwar commission estimated that the total number of casualties may be as high as 800,000 killed by the flood. After the flooding, the Yellow River was diverted from its earlier course at Huayuankou, and flowed into the Jialu River in Zhongmu County. The new course led the Yellow River into the Shaying River at the city of Zhoujiakou (now Zhoukou), eventually joining the Huai River. Water overflowed from these smaller rivers, causing widespread destruction in the basin. According to a postwar report, floods inundated 32 percent of land and 45 percent of villages in 20 affected counties. Controversy regarding the strategy The strategic value of the flood has been questioned. Japanese troops were out of its range, either to the north and east or to the south. Their advance on