On September 10, 1971, Chairman Mao, who was on the southern tour, suddenly changed his itinerary and returned to Zhongnanhai safely on the evening of the 12th. Lin Biao knew that the conspiracy was exposed and decided to flee. In the early morning of September 13, Lin Biao, Ye Qun, Lin Liguo and others took a Red Flag bulletproof car to Shanhaiguan Airport despite the obstruction of the guard force. Take off forcibly without a co-pilot and a pilot. After nearly two hours of flight, the plane crashed on the grassland northeast of Wendurhan, the Mongolian People's Republic.

Shortly after Lin Biao's plane was destroyed, Chiang Kai-shek , who was in Taiwan, also received news, and his heart was mixed. At this time, his eldest son, Jiang Ching-kuo, reported to him that a material about Lin Biao was found in the top secret archives, and the main content was a secret conversation between Dai Li and Lin Biao in the winter of 1941. At that time, Chiang Kai-shek was already old and had poor eyesight. He specially brought reading glasses to read the material carefully. After reading it, Chiang Kai-shek was very angry and said to Chiang Ching-kuo beside him: "Yunnong (Dai Li's word) is a big deal for me!"
Dai Li was one of Chiang Kai-shek's "Thirteen Grand Princesses". He was loyal to him and made many contributions to him. Chiang Kai-shek trusted Dai Li very much and regarded him as his direct confidant. He entrusted him with important tasks many times, and encouraged him even more. So why did Chiang Kai-shek say to Chiang Ching-kuo this time, "Dai Li ruined my big deal"? This starts with his win over Lin Biao. As early as the Whampoa Military Academy period, Lin Biao was appreciated by Chiang Kai-shek for his outstanding military talents. He had won him twice, but failed for various reasons. After the failure of the Great Revolution
, Lin Biao embarked on the road of anti-Chiang. During the Agrarian Revolution War, Lin Biao's military talent was further demonstrated, defeating the national army many times on the battlefield and gaining fame. Whenever this happened, Chiang Kai-shek would regret his failure to win over Lin Biao. After the outbreak of the Anti-Japanese War, the Kuomintang and the Communist Party cooperated to fight against Japan. The main force of the Shaanxi-North Korean Red Army was reorganized into the Eighth Route Army. Lin Biao became the commander of the 1115th Division. He also fought against the Japanese invaders in the Pingxingguan Battle, breaking the myth of the invincible Japanese army and greatly inspiring the people of the whole country's enthusiasm for anti-Japanese war.
Shortly after the war, Chiang Kai-shek sent a congratulatory message, praising Lin Biao's performance. During the Pingxingguan Battle, the Eighth Route Army seized a lot of military supplies, and Lin Biao picked up a military coat and an Eastern Ocean horse. He loved this Oriental horse very much and often walked his horse. One morning, Lin Biao was racing on the ridge wearing a captured Japanese military coat and riding an Eastern horse. Before I knew it, I came to the defense area of Yan Xishan's troops. The sentry mistakenly thought it was a Japanese officer and shot Lin Biao injured.

Yan Xishan After receiving the news, he personally brought the military medical officer to visit and expressed his desire to severely punish the sentinels who caused the accident. However, Lin Biao pleaded for the sentry generously, believing that he had performed his duties and was not wrong, so he asked Yan Xishan not to punish him. Lin Biao's words saved the sentry's life. Due to the injury to the nerves, Lin Biao was sent to the Soviet Union for treatment. In October 1941, Lin Biao, who had improved health, returned from the Soviet Union. When he passed by Xi'an, he lived in Qixianzhuang , which is the location of the Eighth Route Army's office in Xi'an.
After Chiang Kai-shek learned of this, he immediately ordered Hu Zongnan and Dai Li to visit Lin Biao to Qixianzhuang, and instructed Dai Li to find ways to win over Lin Biao and let him use it for his own purposes. Hu Zongnan first fought the front station, and then Dai Li talked with Lin Biao alone for one night. After returning from Qixianzhuang, Dai Li was very excited and started writing a report to Chiang Kai-shek without even sleeping. Hu Zongnan judged from his expression that there was hope for winning over Lin Biao this time. After returning to Chongqing, Chiang Kai-shek asked about the progress of the matter, and Dai Li tried to deal with it without truthfully reporting it.

So why did Dai Li do this? Later, some people speculated that Dai Li was very happy and was unwilling to uncover the lid before the meal was ready, and wanted to wait until the matter was finalized before reporting in detail. Then you can unexpectedly place an satellite , and everyone will look at him with admiration again.Due to Dai Li's deliberate concealment, Chiang Kai-shek thought Lin Biao was not interested in him, so he no longer asked about the matter, so he missed the best opportunity to win over Lin Biao. After the "September 13 Incident", Chiang Ching-kuo accidentally found the report that Dai Li and Lin Biao had had a night talk. After reading it carefully, Chiang Kai-shek realized that it was not Lin Biao who was not interested in him, but was concealed by Dai Li. Then he said angrily: "Yunnong missed me a big deal!"
Main reference materials in this article: People's Daily "Revealing: Why did Lin Biao and Chiang Kai-shek not parted after several contacts"