The Japanese advance from 1937 emptied cities and whole provinces: universities, factories and government offices moved west to Sichuan and Yunnan, and civilians fled ahead of the front in numbers that contemporary and later estimates place in the tens of millions, among the largest displacements of the century. On 9 June 1938 Chiang Kai-shek ordered the Yellow River dykes cut at Huayuankou in Henan to halt the Japanese advance on Wuhan. The flood inundated some 1.3 million hectares across 44 counties, displaced close to four million people and, over the nine years before the river was returned to its course in 1947, is estimated to have killed more than 800,000. The flooded zone contributed to the Henan famine of 1942-43, in which one to three million people died. Chinese war deaths overall are variously estimated at 14 to 20 million. The dyke breach was carried out by the Chinese government against its own population and was concealed at the time as a Japanese bombing.
The Japanese invasion drove tens of millions of Chinese civilians from their homes, and Chinese Nationalist forces breached the Yellow River dykes to slow the advance
China had no reliable national census before 1953. Nationalist government estimates for the late 1930s ranged from 450 to 500 million, and modern reconstructions by Ho Ping-ti and the Maddison project put the population around 500 million in 1937. The 1953 census, the first modern enumeration, counted 582.6 million.
The range is for the Yellow River flood alone. Diana Lary gives half a million as the lowest estimate of deaths; the Disaster History project gives more than 800,000 deaths across Henan, Anhui and Jiangsu between 1938 and 1947, with postwar Chinese calculations reaching 893,303. Total Chinese deaths in the war with Japan, from combat, massacre, famine and disease, are usually put at 14 to 20 million and are not counted here.
The deliberate destruction of the dykes and the resulting inundation and famine are documented in Chinese military orders, relief agency records and the postwar surveys analysed by Diana Lary and by the Disaster History project.
China