On the evening of September 18, 1931, the Japanese Kwantung Army stationed in Northeast China, in accordance with a carefully plotted conspiracy, had the "garrison team" blow up the South Manchurian Railway track near Liu Tiao Lake in Shenyang and charged the Chinese army with this sabotage. This is the so-called "Liu Tiao Lake Incident". Using this as an excuse, the Japanese army suddenly attacked the Chinese army stationed in Beidaying, Shenyang. Because the Northeast Army adopted the "non-resistance policy", the Japanese army occupied Beidaying that night and captured the entire city of Shenyang the next day. The Japanese army continued to attack the vast areas of Liaoning, Jilin and Heilongjiang provinces. Within four and a half months, the whole Northeast China, 1.28 million square kilometers, which is equivalent to 3.5 times the size of Japan's land territory, was completely occupied and more than 30 million people became refugees. This is the shocking "September 18th" Incident.