Lugou Bridge in Beijing. On the night of July 7, 1937, Japanese troops stationed near Lugou Bridge in the southwest of Beijing demanded entry to nearby Wanping county on the pretext of searching for a missing soldier. The Chinese military rejected the order and the Japanese bombed the county seat and Lugou Bridge. Historians agree that the attack signaled the beginning of Japan's full-scale invasion of China, though Japan had invaded the Northeast in September 1931. [Photo/IC]