Oriental Satellite TV once had three episodes of documentaries to describe the Battle of Songhu, which did not contain much content, but it was still very reasonable to say a sentence, saying that in the Battle of Songhu, both sides misestimated each other.
From the point of view of the National Government, the National Government was politically dependent on the mediation of the great powers, they believed that Shanghai was an international metropolis in the Far East, and the Western countries would certainly not stand idly by for their own interests, so as long as they insisted for a while, they would certainly be able to wait for reinforcements, but at that time, Britain and France were being greatly enlarged by Germany, and their attention was focused on Europe, and there was no way to go to Shanghai to support the Kuomintang, and the United States was at that time a domestic isolationism was prevalent. So it was not realistic for the United States or Britain and France to come to Shanghai, and China was not the core interest of these countries at that time.
In addition, Chiang Kai-shek also underestimated the gap between the tactical literacy of the Nationalist army and the Japanese army in the military. They think they are fighting at home, relying on the superiority of troops, and they are also their base camp, at least they can fight a tug-of-war. But in fact, Shanghai is located at the mouth of the Yangtze River, which is conducive to the Japanese army to build a three-dimensional firepower of sea, land and air. After the fighting broke out, Chiang Kai-shek found that the tactical quality of the other side was completely different from his own, but even so, Chiang Kai-shek still fantasized about being able to mediate, and hesitantly refused to withdraw his troops, which made hundreds of thousands of troops densely packed in this part of Shanghai, and were bombed by Japanese planes every day, so it was reasonable that in this war, the death and injury of the Nationalist troops was also reasonable.
But from Japan's perspective, Japan underestimated the determination of the Chinese military and civilians to resist. In the early days of the Soviet-German war, Germany also underestimated the Soviet Union's determination to resist, they believed that as long as their own large army suppressed the territory, the opponents of the other side would rise up, want to overthrow the current government, the country will also be chaotic, did not expect to really fight but found that the various forces of the Soviet Union hate each other, and they have to play with their own lives. For example, at the time of the Battle of Songhu, the Gui army and the Sichuan Army all took out the old books and fought a decisive battle with the Japanese army. In the eyes of the Japanese, these miscellaneous pieces should take advantage of this opportunity to quickly beat up Chiang Kai-shek. Why at this time they had to beat me through the passage was beyond the expectations of the Japanese.
The Battle of Songhu was indeed a defeat, and the disadvantages of the old-style army in the war were clearly seen in front of the modern army, but the attitude of the Chinese soldiers was very clear, it was impossible to surrender, and I want to spend it with you. Therefore, from the time of the Battle of Songhu, the Japanese still wanted to win a quick victory, but unfortunately, their ideas were doomed from the beginning to be impossible to achieve.