Ouyang Xuan's letter to Cao Ergou was only four words, and it was these four words that kept the new annexed army in the city alive. Although Cao Ergou didn't understand why Ouyang Xuan suddenly changed his mind, he recognized that the four words "surrender and avoid death" were indeed Ouyang's handwriting, and even if he agreed, he asked to surrender. Most of the people in the city were overjoyed, but a few tried to resist to the end, but they were tied with their hands and feet and handed over to the Thunderbolts along with their weapons. Some of these people were Chang Yuan's henchmen, while others had their hands stained with the blood of the common people, and they knew that their crimes would definitely be liquidated. The attitude of the Thunderbolts towards these new annexes was that the capital crime was avoidable, but the living crime was inescapable.

The reason why Ouyang Xuan changed his mind was not only because of Li Shuang and Lu Dezhi's dissuasion, but also because after the order to "eliminate all evil" was given, he also faintly felt that something was wrong. The reason for Li Shuang's objection was from an economic point of view, although there were more than 100,000 people under the current rule of the Thunderbolt Army, due to the rapid expansion of various undertakings, there was an extreme shortage of labor. It is only that the Mongols are unruly, but the soldiers of the new annex army are excellent laborers, and it is most suitable to send them to the mines for labor after being captured. Lu Dezhi's reason is that his compassionate heart is overflowing, he believes that God has the virtue of a good life, and should kill less and kill carefully, and he still chanted in his mouth, "Heaven and earth are not kind, and all things are dogs", which makes people cry and laugh.

What made Ouyang Xuan finally write a letter to Cao Ergou was Yang Xiucai, who was in charge of the prison, who also said four words: "rule the country by law". These four words made Ouyang Xuan suddenly realize that his order to "eliminate all evil" was not only inappropriate, but would even bring great losses to the Thunderbolt military industry. Politically speaking, if we blindly wipe out the encircled enemy, it will inevitably make the Mongolian army, especially the newly annexed army, a beast in the future battle, which is not conducive to the use of political means such as division and disintegration. Militarily speaking, people will burst out of strong combat effectiveness due to the desire to save their lives in a desperate situation, and if they do not accept surrender, the new annexed army will fight to the death, which will greatly increase the casualties and ammunition consumption of the Perak soldiers; From the perspective of the rule of law, although Ouyang Xuan is a man of his word in the Thunderbolt Army, he must not override the collective decision-making of the individual. Although "surrender without killing" was proposed by Ouyang Xuan himself, after being discussed and adopted by the military-political joint meeting, it is no longer a personal proposition but the basic policy of the Thunderbolt Army. As a person in a higher position, he cannot govern according to his personal likes and dislikes, let alone change his orders overnight.

Without boats and unable to build a pontoon bridge, the Mongolian troops on the east bank of the river stared at the sound of artillery in Jiangyuan City but were helpless, and they did not even dare to approach the river - if they were close to the river, they would be shelled, so they could only send scouts to observe secretly. After Cao Ergou took over Jiangyuan City, he immediately raised the flag in the city. The Mongolian army on the east bank of the river saw the big word "Cao" and knew that Jiangyuan had been recaptured by the Thunderbolt army, so they retreated. The areas occupied by the Mongol army also have summer grain to harvest, and there is also a serious shortage of labor due to the serious exodus of the population. The Mongols and Semu people disdained to work, so these new soldiers naturally needed to go back to harvest the summer grain as soon as possible.

Just as the main force of the Mongolian army retreated, the half of the Mongolian hundred-man team that set fire was also at the end of its rope. Under the suicidal attack of Xia Dagen with two boats, some of the horses of this Mongolian cavalry fell into the river and drowned, and some remained on the east bank of the river, so that they could only do one man and one horse. This can be done with ease before the Thunderbolt cavalry chase. After all, they can shoot arrows from afar, but they can still run if they can't beat them, and the Thunderbolt army can only hold the walled city and the reclamation point, but they can't hold the vast wheat fields at all. The ripe straw of the wheat field had become dry and crispy under the scorching sun, and when ignited by the fire oil, it became a prairie fire, and for a time it crackled, and the air was filled with the smell of wheat, burnt paste, and soot.

The Mongolian cavalry set the fire while driving away the crowd that came to put out the fire. Many of the people in the crowd were Thunderbolt soldiers who participated in the harvest, and they knew that they could not confront the Mongol cavalry in this plain, so they had to retreat far away. Under the organization of the officers, the crowd retreated in an orderly manner to ditches and ponds where horses could not charge, formed defensive formations, and began to establish fire barriers to stop the fire from spreading into the distance. Fortunately, although the wheat field is dry, the firebreak does not need to be too wide due to the short and short plants. There are also a number of ditches and ridges between the wheat fields, which also slows down the spread of the fire.

The cavalry of the Thunderbolts followed the smoke. Although the cavalry of these two companies was also one man and one horse, because they benefited from the harvest of the widow's cliff, they rode all healthy horses, and the weaker war horses were eliminated to make mail horses, so the speed of travel was not much worse than that of the Mongol cavalry, and after a while they caught up with the Mongol cavalry who set fire to it. The Mongol cavalry had no choice but to set fire to it while fleeing north. It's just that due to the gap in horsemanship, the Thunderbolt cavalry has never been able to catch up with the Mongol cavalry, and on several occasions they almost lost their target. In the vicinity of Wuyouyi, more than ten miles north of Chongqing Prefecture, the commander of the Thunderbolt Army saw that the Mongolian cavalry was erratic, so he divided his troops into two ways to flank the Mongolian cavalry.

The strategy of splitting the troops and attacking them from two sides gradually paid off, and by the time they reached the vicinity of Yongkang County, the Mongol cavalry had been surrounded. In front of them was Longmen Mountain, to the left and right were the Thunderbolt cavalry, and behind them was a wide ditch with an array of infantry lining the only bridge in the ditch. The first three rows of the array were giant shields, and behind them were dozens of dense rows of spearmen. Seeing that there was no way to go in front and behind, and the cavalry of the Thunderbolt Army on the left and right approached step by step, the leading Mongolian cavalry suddenly drew his sword and killed the cavalry next to him, and shouted loudly in stiff Chinese: "Surrender, surrender", and the rest of the Mongolian cavalry saw that they threw their weapons into the distance, and then dismounted and knelt down.

The Mongol cavalry that led the surrender just now was a Khitan, and the cavalry that was killed was a Mongol, and their role in the army was like that of a supervisor. For the past two days, this cavalry has been doing evil all the way under his coercion, and now that he is dead, the rest of the Mongolian cavalry dares to surrender. The surrendered Mongol cavalry remained thirty-one people, who lost more than twenty on the way to pursuit. Some of these horses were captured and wounded by falling into a ditch, some were killed and wounded by the artillery of the forts along the way, and many more were killed by the Thunderbolt cavalry with firearms. The Thunderbolt cavalry, which followed the pursuit, did not fight with the Mongols on horseback, but pursued them close and dismounted, and bombarded them with light cannons. If the Mongol cavalry rushed closer, they switched to muskets and grenades. Since the Mongol cavalry that set fire to the fire was much smaller than the Thunderbolt army after the division, the latter situation occurred only twice, and each time it was met head-on.

The Jiangyuan Incident caused heavy losses to the Perak Army, not only more than 50 civilians were killed, but also more than 20 soldiers were lost. In terms of supplies, most of the dozens of transport ships that were hijacked were damaged, Jiangyuan City was damaged a lot under the shelling, and the Shiyu Tun reclamation site was turned into a blank field. What is particularly sad is that although the rescue was timely, nearly 1,000 mu of wheat fields were still burned, and about 200,000 catties of grain were lost, which made the people of Jiangyuan grit their teeth when they mentioned Chang Yuan. In view of the great anger of Chang Yuan and his gang, Yang Xiucai was severely and severely sentenced to death during the trial. The 500 surrendered new annexes were also executed, and the rest were sent to the mines for labor reform. As for the Mongol cavalry who surrendered, they cut off the three fingers of their right hand according to the old method and gave them to Weimao and Weimao for free, and they sold them to the grasslands north of Songzhou.