On the morning of 8 December 1941, Japanese forces bombed Kai Tak Airport, wresting control of the skies from the British and initiating the Battle of Hong Kong. At noon, the Japanese advance guard crossed the Shenzhen River to invade the New Territories. The northern garrison fell back to the Gin Drinkers Line, destroying roads and bridges on the way to make it more difficult for the invaders. By dusk, the Japanese had taken Tai Po.