The Marco Polo Bridge Incident is a battle that occurred between the Chinese and Japanese armies in 1937. A dispute broke out that led to gunfire at the bridge, which developed into a war between the two sides that lasted 8 years.
The war resulted in more than 22 million casualties, most of them Chinese civilians. The number of Japanese casualties reached about 2.1 million, while the Chinese side lost 3.2 million. After the Japanese Empire took control of Manchuria Province in 1931, it wanted to expand and occupy more lands in China and Southeast Asia.