Although the three armed merchant ships and two light artillery squads were not enough to change the situation on the battlefield, or even to prevent the Mongolian army from freely coming and going on the east and west banks of the Min River, they made the Meizhou naval army suffer a lot from the protection of the siege equipment on both sides of the strait. Yu Xing ordered three armed gunboats to take the lead, and then carried two squads of light artillery onto the ship, taking advantage of the range advantage and fighting a guerrilla war with the Meizhou naval army. This put the Meizhou naval army in a dilemma, chasing it will face the blow of the siege equipment on the city wall, if it stops in place but can only be beaten in vain and cannot return fire, if the retreating warship is safe, but the transport ships coming and going between the two sides of the strait will be shelled, and the horizontal and vertical are in a dilemma.

Liu Daer also tried to deal with it with gunboats, but the few imitation fortress cannons in Meizhou were clumsy and not suitable for being on board. After the first shot, the Jiading naval ships were unscathed, and the Meizhou gunboats were sent to the bottom by the huge recoil. It is said that the navy is a technical service, and the gunboat is a combination of current high technology, not only the ship has special requirements, but also the marine artillery must be specially designed, in line with the requirements of light weight, small recoil, wave proof and waterproof, etc., and the requirements for the gunner are also very high. To operate in confined spaces and hit the opposing moving ship in the face of bumpy waves, it takes a long period of training.

Yu San did not order the gunboats to attack back the water, but only patrolled the waters next to Jiading City, on the one hand, his task was to help defend Jiading City rather than destroy the enemy, and on the other hand, he also had to save ammunition. The three armed merchant ships were now less than half of their ammunition, and the light guns of the two gun squads had only a few dozen rounds of ammunition left. At present, Jiading is already in the lonely city, and one shot of these ammunition will be missing. Yu Sande used these ammunition and the grenades, mines and other firearms he brought to defend the city at the most critical moment. Although Jiading City can also produce black powder, the quality is far inferior to that produced by the Thunderbolt Army, and even if it is barely used, the range and lethality of the artillery will be greatly reduced.

After a few exchanges, the war entered a state of calm before the war, and both sides were fighting fiercely. At this time, Cao Zhizhou had captured Hongya and Jiajiang counties, and was coming to Jiading along the Tsing Yi River. Cao Da'er was building more siege weapons and driving Minzhuang to dig a trench in front of Jiading City. He was not in the camp in front of Jiading, but set up the big tent in the ravine behind the logging camp. As a Mongolian in the bitter cold land of the north, he, like the Mongolian cavalry under his command, could not stand the humid heat and heat. Although it was late May, which was not the hottest time in Shu, these Mongol cavalry did not plunder the countryside as often as before, but only sent a large number of rangers to reconnoitre.

In the blink of an eye, in early June, Cao Zhizhou's Yazhou army also arrived downstream, realizing Liu Daer's three-way joint attack on Jiading City, and the Mongolian army gathered under Jiading City at this moment totaled 12,000 people. After Liu Da'er surrendered to Mongolia, the garrisons of Meizhou counties were all attached to his banner, and he forcibly recruited a large number of people as soldiers, and his strength expanded a lot. However, in order to piece together the 2,000 soldiers and horses that attacked Jiading, he also used the power of the wilderness, so that most of the people who guarded Meizhou City and its subordinate counties were strong. He was not worried that the Thunderbolt army would take the opportunity to attack, on the one hand, he told him that the secret man Huoli had led a large army to approach the Guankou village of the Thunderbolt army, and on the other hand, the Mongolian army was about to go south and seize Pengshan City with the cooperation of Neiying. At that time, the Thunderbolt army will have no time to take care of itself, and there will still be troops there to attack Meizhou.

There were more than 3,000 soldiers brought by Cao Zhizhou to Jiading City, more than the people brought by Liu Da'er. Yazhou is not as poor as Meizhou, it is not easy to piece together so many soldiers, you must know that Yazhou also arranged heavy troops in the famous mountain city to prevent the thunderbolt army, and also left soldiers and horses in Yazhou City and Lizhou, Diaomunzhai and other places. The reason why he was able to send so many soldiers and horses this time was not only because Cao Zhizhou was desperate to expand the army, but also because he attracted a lot of Yibo and Qingqiang tribes this time, and these tribes produced a total of 1,000 people. He promised these tribes that after the deed was completed, he would allocate large tracts of land to Jiading and Meizhou for their cultivation, and grant them the right to trade in the Yibo region.

With the strong support of the Thunderbolt Army, Ze Hao has changed from the lord of a cottage to the leader of more than a dozen cottages and three grassland tribes, and the population under his rule has exceeded 10,000. At present, the archery furnace is not only strong and strong, but also has become a trade center for five hundred miles around, and it makes a lot of money just by collecting tolls, which makes other Yibo tribes very red, and Cao Zhizhou just promised this what this tribe wants most. As for the land in Jiading and Meizhou promised by Cao Zhizhou, it is also very credible. Due to the frequent disasters of swords and soldiers, the entire western Sichuan has idle a large amount of land, and both Cao Zhizhou and Liu Daer are recruiting laborers to come to the reclamation. It's just that their rampant conquest is only a little better than that of the Mongols, and most of the displaced people are still heading for the Perak army.

The addition of the barbarian soldiers of the Yibo tribe greatly enhanced the strength of the Yazhou army, but it also brought endless troubles to Cao Zhizhou. These Yibo soldiers were strong but unable to see each other, they did not listen to the command at all, and even dared to clash with Cao Zhizhou's personal soldiers, and each of them killed and injured more than ten people. Cao Zhizhou's daily energy was mostly spent on pacifying and coaxing those Yibo leaders, and he was overwhelmed. After capturing Hongya and Jiajiang City, these Yibo soldiers were brutal, like a bull that broke into the porcelain shop, they went on a rampage, killing people when they saw people, robbing them when they saw property, and at the end they burned the city with a fire, and they didn't plan to leave some residues for the Yazhou soldiers behind. Fortunately, the fire was extinguished, otherwise Cao Zhizhou would have gotten a blank field. It is said that he has now regretted recruiting these barbarian soldiers of the Yibo tribe.

There were a total of 7,000 troops in Jiading, including 5,000 new troops and 2,000 cavalry. These new annexed troops came from Jianzhou, Longzhou and other places, and all of them had reached the west bank of the Minjiang River at this time, and they would attack the city together with Liu Daer and Cao Zhizhou. In addition to serving as a scout and covering the siege of the new annexed army, the most important role was to supervise the army. The other 1,500 cavalry remained on the east bank of the Min River, and their role was to prevent the Song army from the direction of Luzhou from attacking from the direction of Zizhou, Longzhou, and Fushunjian.

The Mongolian army outside the city is in full swing of preparations, and Jiading City is not idle, and it is also in full swing to prepare for war. Zan Wanshou selected dozens of brave and dead soldiers to rescue Luzhou, Chongqing, Banzhou, Xuzhou and other places, and even sent messengers to the Yiren tribes in the south of Jiading and Duzhangman on the border of Xuzhou. In the letter, he knew the benefits and harms of Chen Jiading falling into the hands of the Mongolian army, and hoped that reinforcements would fight against Mongolia together. Zan Wanshou did not distrust Ouyang Xuan's promise to come to help, but felt that the imperial court and friendly forces would not sit idly by, and even had a fluke mentality towards the barbarian tribes, feeling that they might send assistance because of the cold of their lips and teeth. Yu San collected all the sulfur in the city, sent people to scrape the wall nitrate, mixed it with charcoal to prepare hundreds of catties of black powder, and made a lot of improvised bombs with small clay pots. Although these improvised bombs are not as powerful as the Thunderbolts, they are more than enough to bomb people or destroy siege equipment.