Introduction to the Battle of Songhu: The Battle of Songhu, also known as the August 13th Battle, was called the Second Shanghai Incident in Japan. It was the first large-scale battle between China and Japan in the Anti-Japanese War, and it was also the first large-scale battle fought in the entire Sino-Japanese War. The largest and most brutal battle. During the Battle of Songhu, the Japanese army suffered heavy losses due to the stubborn resistance of the Kuomintang. For China, this battle marked the true beginning of an undeclared war between the two countries and a full-scale war. The regional conflict after the Marco Polo Bridge Incident escalated into a full-scale war. , and completely shattered Japan's "three months to destroy China" plan.