This traitor is Liu Zheng, a standard Han Chinese, who was born in Henan of the State of Jin at that time. Later, when the State of Jin perished, Liu Zheng surrendered to the Southern Song Dynasty and became a general of the Southern Song Dynasty. This Liu Zheng is brave and has the reputation of "filial piety", that is to say, he is braver than the valiant soldier Li Cunxiao. This Liu Zheng once took only 20 men to lay down Xinyang, the important town at that time, and captured Xinyang's garrison commander alive, which was as powerful as Xiang Yu's 300 men to seize the city.
Later, the Mongols continued to attack Sichuan, and the troops were tight, so Liu Zheng was sent to Sichuan, and made meritorious military service repeatedly, becoming the most intrepid general in the Southern Song Dynasty. It can be said that he could not die in the Southern Song Dynasty. However, although Liu Zheng was brilliant, capable and brave, he was not reused under the fatuous rule of the Southern Song Dynasty at that time, but was excluded. On the one hand, at that time, the Southern Song Dynasty was very uneasy about the "returnees" fleeing from the north, thinking that they were traitors after all. On the other hand, more importantly, Liu Zheng's ability has made many generals jealous.
Once Liu Zheng went to help Jiading Shoujiang Yu Xing resist the attack of Mongolian army, but this Yu Xing looked down on Liu Zheng, not only didn't meet the reward as usual, but also complained a lot. Liu Zheng was so angry that he could only fight Yu Xing's men. As a result, Yu Xing embarked on the road of revenge against Liu Zheng. On the one hand, Liu Zheng made meritorious service, which he concealed, but also punished them. Finally, Liu Zheng's grain and grass were directly detained and could not survive.
At this time, Liu felt that if this continues, his life may be lost. As a result, he quickly led "300,000 households in 15 counties of Luzhou with a capital of over one million" to surrender to the Yuan Dynasty. Liu Zheng's rebellion directly dug the grave of the demise of the Southern Song Dynasty. Because Liu Zheng fought in the Southern Song Dynasty for a long time, he knew the weakness of the Southern Song Dynasty and the mistakes of the Mongolian army. To this end, he put forward two suggestions to Kublai Khan, directly destroying DaSong.
First, the Mongolian army always carried out the strategy of attacking Sichuan first and outflanking the Southern Song Dynasty in the southwest. But after playing for decades, I always stumble in the fishing city (now Chongqing). That year, Mongolian Khan died in the fishing city, but the one-track-minded Mongols later implemented this strategy, always in vain. Liu Zheng pointed out that this strategy is wrong. Xiangyang was the throat of the Southern Song Dynasty. After winning Xiangyang, the first city in the Southern Song Dynasty, Lin 'an, the capital of the Southern Song Dynasty, was unable to be immune. Therefore, we must go to Xiangyang first, and then take Lin' an as the biggest strategy.
Second, the Southern Song Dynasty had the most advanced naval forces at that time, and the main fortresses were basically around the Yangtze River. Therefore, without the water army, it is difficult to win simply by relying on iron soldiers. Therefore, Liu suggested that Kublai Khan train the water army and personally served as the training of the water army. Kublai Khan felt quite right after hearing this, and immediately acted according to Liu Zheng's plan. Soon, Xiangyang fell and the Southern Song Dynasty soon perished.