Ouyang Xuan did not go south to command the Battle of Jiading. On the one hand, he stayed in Chongqing Mansion to coordinate the entire battle situation, after all, the secret Huoli is currently under the Guankou Walled City, and the direction of Weimao and Yazhou may also change dramatically, and he needs to be in command. On the other hand, it is because many new technologies are currently being developed at a critical moment and require his guidance and coordination. Although the new gunpowder he was most interested in had been successfully developed, it was still some time before the next step of industrial production, and in addition to the reason that the manufacturing equipment could not keep up, there was also a lack of many key raw materials, and it was necessary to find alternative materials. Significant advances have also been made in microscopy, penicillin, and vaccinia inoculation, and these techniques, once applied, will have significant implications for reducing mortality.

The battle to Jiading in the south was commanded by Chief of Staff Huang Dagen, and Le Quanan and Cao Ergou led their troops to advance by land and water. They will first attack Meizhou, and then go south to support the defenders of Jiading. If Jiading City is compared to an anvil, the Thunderbolt Army is a sledgehammer that swings at the Mongolian army of the New Ring. According to Ouyang Xuan's requirements, even if he can't completely annihilate the Mongolian army, he will still be beaten, especially Liu Daer and Cao Zhizhou, the two traitors. After these two people openly surrendered to Mongolia, many Song generals and colonels on the Sichuan battlefield also followed suit and sacrificed cities and fortresses to surrender to Mongolia, but fortunately, the scale was not large, and the impact was not as bad as the two.

Starting from the waterway, it was the majority of the naval brigade, and Le Quanan only left half a battalion of regular naval troops to defend along the Jinma River. This half battalion seems to be small, but with the support of several backbone water militia battalions along the line, there is no problem in preventing the Mongol army from crossing the river. The reorganized naval brigade has three main battalions and one brigade headquarters battalion, and the main battalion has one heavy artillery ship company, two light artillery boat companies, and two escort ship companies under its jurisdiction, and is equipped with three heavy artillery boats, 10 light artillery boats, and 20 escort ships. This time, Le Quanan brought a total of three heavy artillery companies, four light artillery companies, and five escort ship companies, equipped with a total of 72 heavy artillery pieces, 80 rapid-fire guns, and dozens of light small guns of various types, as well as a number of demolition boats, reconnaissance ships, and a large number of baggage transport ships, including more than 300 large and small ships, more than 1,300 soldiers, and more than 1,000 militiamen.

The field division, which marched by land, was fully equipped with 4,500 men, and with the accompanying more than 5,000 militiamen, the number exceeded 10,000. These units were divided into three teams, the front, the middle and the rear, with a cavalry brigade of 1,500 men at the front. The seizure and the purchase of a large number of war horses from the Tibetan region made the cavalry brigade reach one man and two horses, and the number of war horses has reached more than 3,000, and the mobility is no longer inferior to that of the Mongolian cavalry. However, at present, the cavalry of the Perak Army still belonged to the category of mounted infantry, and after they arrived in Meizhou, in addition to sending reconnaissance cavalry to all directions, they immediately began to build fortifications, and planted mines on the official road leading to Jiading in case of a sudden attack by the Mongol cavalry. In fact, the Mongol cavalry had only a few scouts on the border of Meizhou, so the results of the mines were extremely limited.

The cavalry was followed by two light infantry battalions and two heavy infantry battalions of two infantry brigades, totaling 2,000 men. An infantry brigade of a field division has two light infantry battalions and one heavy infantry battalion, both of which have five companies under their command and are also equipped with standard weapons such as spears, giant shields, muskets, and grenades. The difference between them was that they were armed with different field guns, the heavy artillery battalion was armed with forty-five heavy field guns, while the light artillery battalion was armed with ninety light field guns. These field guns were mounted on wheels and dragged by mules and horses, and were able to keep up with the infantry.

At the back of the marching column was naturally a logistical baggage contingent composed of the backbone militia. The Perak Army implements the integration of farming and warfare, and these basic militias are all ordinary people in the prime of life, and they are also trained on weekdays, although the weapons brought by the army this time are mostly cold weapons, but the combat capability is actually not inferior to the new annex army with a comparable number of people. Fighting a war is a logistical battle, and especially for the Thunderbolt Army, which uses firearms as its main combat weapon, it is even more important to protect the logistical baggage, and there is no room for even the slightest loss. In line with the principle of "carefully sailing the ship for ten thousand years", Cao Ergou specially transferred two light infantry battalions to protect the logistics baggage. The terrain of Meizhou and Jiading is mostly hilly and low mountains, and the official road from Pengshan to the two places also runs through the ravines between the hills or in small basins. In order to prevent the Mongol cavalry from raiding, Cao Ergou not only sent a large number of reconnaissance cavalry forward, but also ordered the lightly armed infantry to advance along the mountain roads on both sides of the official road to cover the two flanks of the large army.

Zhou Jianshen's deception made Liu Da'er fall into an ice cellar, and he angrily scolded the Thunderbolt Army for being insidious and cunning Zhou Jianshen was not trustworthy, and begged Niu Ling to send troops to aid Meizhou City. Before, he thought that after Pengshan surrendered to Meng, Meizhou City naturally sat back and relaxed, so Meizhou City and its subordinate counties did not have many troops, and even a lot of artillery at the head of the city was taken by him to attack Jiading City, which could withstand the two-way attack of the Thunderbolt army. What's more, the loss of Meizhou City will inevitably affect morale and even make the soldiers mutiny. Most of the soldiers under Liu Da'er are from Meizhou and its subordinate counties, and they are already resentful when they are forcibly conscripted, and if their wives and children fall into the hands of the Thunderbolt army again, they will naturally be unstable.

The terrain of Jiading City is dangerous and easy to defend and difficult to attack, coupled with the proper command of Zan Wanshou and the support of the Thunderbolt army, although the Mongolian army is several times the number of the defenders, it cannot attack the city. It is worth mentioning that although Yu San led the special company of the Perak Army with few people, he played the role of the firefighting team, and used firearms to dismantle the offensive of the Mongolian army at critical moments many times, so that Jiading City could turn danger into a disaster. The news that the Chengdu Mongolian army was heavily damaged by the thunderbolt army that had surrendered by fraud made Niu Ling tremble with anger. Unable to capture Jiading City in a hurry, and seeing that there were police in Meizhou, Niu Ling had to agree to Liu Daer's request and let him lead his troops back to Meizhou for rescue. In order to deal with the southward movement of the Perak army, he transferred 500 cavalry to the west bank of the Minjiang River, and returned to support the Meizhou defenders together with the original 500 cavalry.

Liu Daer led his subordinates to Meizhou along the land and water. It's just that the return trip is going up the water, and the speed can't be fast at all. Although the land route is lightly armed, Jiading is nearly two hundred miles away from Meizhou, and this distance takes two days even for cavalry. It took three to four days for Liu Da'er's elite soldiers to arrive, and his soldiers who had not been recruited long took even longer, and the combat effectiveness of the rapid march to Meizhou would drop significantly. On the other hand, there are only forty miles from Pengshan to Meizhou, and the infantry of the Perak Army can also reach it in the morning and evening, while the cavalry brigade can reach it in half a day. Therefore, when the Perak army's logistics baggage troops arrived outside Meizhou City and began to build a camp, there were sporadic Mongolian cavalry on the official road in the distance, and these scouts were the vanguard of a thousand cavalry led by Kudu. As for the naval army and infantry led by Liu Da'er, they were at least two or three days away.

Cao Ergou ordered the construction of two camps outside Meizhou City, one facing Meizhou City and the other facing the direction of Jiading, which were respectively defended by an infantry brigade. The cavalry brigade waited for an opportunity to attack under the cover of two battalions. According to reconnaissance, the defenders of Meizhou City were only a few hundred, and the people who were driven to guard the city wall were only 3,000 people. In his opinion, it was easy to take Meizhou City, only a heavy artillery bombardment, an infantry charge could be taken, and the only thing to worry about was that the Mongol cavalry would attack from behind while the field division was attacking the city. At that moment, he sent people to contact Le Quan'an, and the field division was fully engaged in dealing with the Mongol cavalry, and the siege was carried out by the naval brigade.