Six and a half years of raids, and the tunnels under the city

The bombing of Chongqing ran from 18 February 1938 to 19 December 1944 and was carried out by the Japanese army and navy air forces against the provisional capital and other targets in Sichuan. Incomplete statistics count 268 raids, with anything from a few dozen to more than 150 bombers at a time. Chinese records for 1938 to 1943 give 9,513 sorties, more than 21,000 bombs of all kinds including biological weapons, 11,900 dead, 14,100 injured and 17,600 houses destroyed, and thirty schools bombed. The fog of the basin made targeting hard for much of the year; only from May to October was visibility good.

The hills gave the city its shelter and its labour. Because the ground is mountainous, air-raid shelters could be dug into it; because it is rock, digging them took hard manual work. What went underground included factories, government offices and the city's radio station, and between 1939 and 1942 eighteen anti-aircraft artillery batteries stood around the city. At the university on the ridge the engineering building took three hits and did not fall, students sheltered underground and went back to their lectures, and a painter worked by lamplight in one of the tunnels.

On the evening of 5 June 1941 the bombers worked over the city for hours, and part of the ventilation opening of a main air-raid tunnel was blown in. Survivors recalled that the people inside crowded towards the entrance for air and pressed on one another in the dark; the city history puts the death toll that day in the thousands, and one record gives 7,764 dead. The date is now a memorial day, and since 1998 the city has sounded its air-raid sirens every year on 5 June. The last recorded raid of the campaign came on 19 December 1944, at Liangshan, Wanxian and Kaixian.