After a heavy rain in late July, taking advantage of the fact that the river was rising sharply and the river was wide, the Perak Army sailed up the Jinjiang River from Pengshan to officially launch a military operation to capture Chengdu. In addition to the naval brigade, the Thunderbolt army in this direction also had two thousand Jiading troops led by Zan Wanshou. According to Ouyang Xuan's order, the naval brigade was responsible for controlling the water surface and providing fire support, and the landing operation was handled by the Jiading army. If only 2,000 people and more than 1,000 people from the naval brigade had attacked Chengdu before, it would have been unimaginable for the officers and men of the Jiading army. It's just that now with the powerful firepower of the artillery warship as the backing, not only Zan Wanshou is full of confidence in victory, but also makes the morale of the reorganized Jiading army high.

After the Battle of Jiading, Zan Wanshou searched for the soldiers of Jiading, Sangui, Jiuding and his subordinate counties, and selected hundreds of soldiers from among the soldiers, and formed six battalions according to the establishment of the Perak army, each battalion was also 500 people. Considering that the war was imminent, Zan Manshou did not make major changes to the command system, but only enriched each company, platoon, and squad with Perak soldiers and officers. After Zan Wanshou secretly joined the Thunderbolt Army system, Ouyang Xuan urgently deployed a large number of grenades, mines and light artillery to the Jiading Army. These light firearms are simple to use, quickly improve the combat effectiveness of the Jiading army, especially suitable for close combat and urban street fighting, and are very suitable for attacking Chengdu City. As for the heavy firepower of the siege, there is no need to worry at all, the firepower of the gunboats of the naval brigade is even stronger than the firepower of the entire field division. As for the enemy camp far from the shore, Le Quanan also patted his chest and assured him that he could dismantle the light ship guns and shoot at them.

To attack Chengdu along the waterway from Pengshan, it was necessary to take the fortress of Guangdu City, which was controlled by the Mongol army. This Guangdu city is located on the bank of the Jinjiang River, less than 50 miles from Chengdu. Liu Heima's raid on Chengdu was plundered and completely destroyed in the battle between Niu Xuan and Pu Xue, so when the Thunderbolt army raided Chengdu at the beginning of the mountain, the city was still in ruins. After the Mongolian army and navy were hit hard one after another, in order to prevent the Thunderbolt army from going north to Chengdu, Liu Heima ordered people to build a new camp on the ruins of Guangdu, and transferred 500 new annexed troops and 1,000 households to Tuntian here, in order to make it an outpost of Chengdu City, delay or even block the Thunderbolt army.

However, even though the new annexed army set up a large number of water barriers in the river and dug a large number of anti-artillery trenches next to the barracks, the Guangdu barracks still fell under the control of the Thunderbolt army within half a day. The fences, iron cables, and hidden piles set up in the river disintegrated on the surface of the powerful blasting ship, and for Le Quan'an, even if the enemy completely blocked the channel with the sunken ship, it was only a little troublesome. As for the rammed earth and timber barracks, they could not withstand the shelling of the heavy artillery on the ships, and they fell apart one after another. The soldiers of the new annex army, who fled into the trenches to avoid the shells, were also routed by the Jiading army, which immediately launched a surprise attack, and scattered in all directions. After the re-selection, the Jiading army was all elite and had high morale, and with firearms, its combat effectiveness was more than doubled, forming a hanging and beating trend for these demoralized new annexed troops.

After taking the Gwangdu fortification, the Perak ships continued to travel north. In the process, the fleet was constantly attacked by siege weapons such as ballistae and catapults erected by the newly attached troops along the river embankment, as well as by fire ships, and a large number of Mongol rangers constantly attacked with rockets, but under the strong fire of the Thunderbolt warships, these attacks of the Mongol army were thwarted one by one. Two days later, Zan Wanshou led the army to ten miles outside Chengdu. Here, the Mongols sank ships loaded with gravel into the channel, blocking the path of the Perak ships. Due to the turbulent water flow and many blockages, it is estimated that it will take more than three days to clean up.

Just when the Mongolian army in Chengdu City was in chaos, Cao Ergou led the field division from Sandu Water to Wenjiang City. According to the plan of the General Staff, after the field division attacking by land took Wenjiang City, it would push all the way to join the water attack force led by Zan Wanshou under the city of Chengdu. The field division was large in size and was followed by thousands of basic militiamen transporting heavy loads, and the movement was naturally not small, and it was detected by the Mongolian army rangers before it crossed the river. In fact, this is also one of the reasons why the General Staff let the naval army act first, and the naval brigade and the Jiading army were under the city of Chengdu, so that the Mongolian army did not dare to transfer troops in the direction of the Wenjiang River on a large scale. Another reason why the sailors moved first was that the road was too muddy and slippery after heavy rains, and they had to wait for the road to dry out before they could march.

Equipped with heavy artillery, the combat effectiveness of the two infantry brigades of the field division has been greatly improved, but it has also greatly reduced the mobility of the army. In order to enhance mobility, Ouyang Xuan and the staff thought of a number of methods, including light artillery erected in carriages, and heavy artillery artillery mounts equipped with iron wheels, and equipped with a large number of mules and horses. It's just that heavy artillery often costs hundreds or even thousands of pounds. Although the light artillery is light, most of them are one or two hundred pounds, and even the light guns used by the cavalry and special forces are forty or fifty pounds. These iron lumps, combined with ammunition, made it difficult for the army to march faster. What's more, in order to prevent the surprise attack of the Mongol army, the Thunderbolt infantry also brought triangular nails, repelling horses, heavy spears, giant shields and other weapons and equipment to defend against cavalry, and these necessary baggage naturally slowed down the marching speed.

The field division still followed the standard marching pattern, in which two infantry brigades protected the baggage convoy in the middle, one in front and one behind, and the cavalry brigade protected the two flanks. On the march, small groups of Mongol cavalry constantly came to harass, but they were all driven away by the cavalry of the Thunderbolt army. Sandu Water is only more than 20 places away from Wenjiang, although the official road is in disrepair for a long time, the roadbed is still there, and the road surface is also flat and wide, so the marching speed is not slow. Before it was early, the field division arrived at Wenjiang City and regained the city in one fell swoop. In fact, the Mongol army attached great importance to this county town close to the Perak army, and led a heavy army to garrison it before the secret was executed. Kublai Khan transferred a large number of Mongolian troops from Sichuan to the north to compete with Ali Buge for hegemony, and the cavalry of the Secret Huoli Division stationed in Wenjiang was one of them.

After the cavalry of the Secret Fire Division was transferred, the new annex army stationed in Wenjiang City had 1,000 people. Although compared with the garrisons of the Sichuan and Western Mongolian Army in various counties, the Wenjiang garrison is considered to be too much, and the most in other counties are only five or six hundred, and the few are even only two or three hundred. It's just that Liu Heima also understood that this city was on the front line of the battle against the Thunderbolt army, and the defense was obviously very important, so he transferred 500 cavalry from Pengzhou to Wenjiang. It's just that two days ago, the Thunderbolt army attacked Chengdu, and forced him to transfer the cavalry back to Chengdu. When the Perak army began to cross the three crossings, Liu Heima understood that the thousand men would never be able to hold the Wenjiang River, so he told the new general of the annexed army defending the city that he would only need to hold out for two days, and he would lead a large army to help, but the defenders did not hold out for even an hour.

In fact, it is not to blame the new annex army defending the city, because the field division is too powerful. Cao Ergou only used an infantry brigade to attack Wenjiang City, and less than half of the artillery was used, but after several rounds of heavy artillery, the gate of Wenjiang City was blasted open, and the siege equipment was destroyed, and dozens of meters on the city wall were also collapsed, and the defenders on the city wall were blown up to the point of flesh and blood, and more than 100 people were killed and wounded in a short time. What can you do if you don't surrender? Want to escape, can you escape the cavalry of the Thunderbolt Army?