Traveling through 1937, starting from the Battle of Songhu

In the Battle of Songhu, 700,000 Chinese people marched forward and fought to the death with the Japanese invaders who had airplanes and cannons. In October of the same year, the abandoned son of the Gu family walked out of the house. After traveling through time, Gu Changfeng, a modern soul, made up his mind to join the war of resistance. Unfortunately, he was dismissed from the army again. Gu Changfeng thought to himself, it's just right, I'm here on the battlefield of Songhu... He collected the defeated soldiers and formed his own army. What? No weapons? The devils can rob them, but I'm a man with a system. ...