Anatomy of an invasion: the Mukden incident of 1931
Chinese historians generally refer to the Mukden incident on September 18, 1931, as the first chapter in the Japanese invasion of China.
On that day, a bomb blast destroyed a railway line near Shenyang, then known as Mukden, and the Japanese army used the incident as a pretext to occupy southern Manchuria. The Japanese completed the occupation of Manchuria and proclaimed the puppet state of Manchukuo in February, 1932, and installed former emperor Pu Yi as ruler.
The full invasion began in 1937 when the Japanese army, claiming to be looking for a missing soldier, attacked Chinese troops at the Lugou Bridge, or Marco Polo Bridge, on the outskirts of Beijing.
The Sino-Japanese war ended eight years later, when the Japanese troops formally surrendered on September 9, 1945.