The main force besieging Jiading City was the Mongol Han Army of Wang Dechen and the new annex army of Yang Dayuan's Department, although these two Mongol armies were good at fighting fortified positions, they did not bargain in Jiading City. Tunnels, fire attacks, car rushes and other siege methods were all used, but they were either thwarted by the defenders or ineffective, so they had to dig trenches and besiege them. Although the strength of the Mongolian army and the navy improved rapidly, and even defeated the Meizhou navy, it could not help the Jiading navy, and the two sides fought equally. Jiading City can still receive a steady stream of support through waterways, so although the Mongolian army is numerous, it will not be able to capture Jiading for a while.

In this stalemate, the main forces of the two sides are bed crossbows and trebuchets. The Mongolian army has a large number of people and the outside of the city is vast, so there are many siege weapons, although the siege weapons of Jiading City are few, but there is a wall dish protection from the high ground, so no one on both sides can suppress anyone. The turning point of the battle came with the arrival of grenades. After the grenades supported by the Thunderbolt Army arrived, a captain in Jiading City had a whimsical idea to throw grenades with a trebuchet. Yu Xing actually didn't care about these old-fashioned grenades given by the Thunderbolt Army, and felt that the throwing distance was short and the damage was small, and the power was far inferior to the artillery, so he immediately had the mentality of giving it a try and allowed to use a trebuchet to fire grenades.

The lieutenant first tested the firing with a grenade-sized stone, and then adjusted the length of the fire rope to determine the time of the explosion. Once ready, a trebuchet was used to start firing grenades. I don't want to get a good result with the first blow. The launch of a single catapult is a probabilistic shot, and it is the norm to miss a hit, but it is an accident if it hits. The test-firing trebuchet was aimed at the Mongolian army's trebuchet, and it did not hit without any suspense, but smashed into the mud two or three meters away from it. Seeing iron bumps falling from the sky, the curious Mongolian soldiers stepped forward to watch. Fearing that the grenade would explode before it could hit the target, the lieutenant kept the fire rope longer. At this time, it suddenly exploded, blowing up the onlookers of the Mongolian army.

After the first victory, the defenders of Jiading threw grenades at the siege weapons of the Mongol army. In fact, the damage of the grenade to the siege equipment is not great, and the killing effect is not as good as that of stones, but the killing effect on soft targets such as personnel is excellent. The shrapnel flying in four places killed or injured the Mongolian troops within four or five meters of the explosion point, completely making up for the shortcomings of the trebuchet's low accuracy. This made the previously evenly matched siege weapons duel completely fall to the side of the Jiading army. Siege equipment can still be made if it is destroyed, but skilled operators need time to cultivate, and if one dies, one will be less.

By the time the Jiading army had dropped all the grenades supported by the Thunderbolts, the Mongol siege force had lost its combat effectiveness - there were still a lot of bed crossbows and trebuchets, but the operators were almost killed or wounded. Although the grenades are gone, there is no shortage of stones. The defenders of Jiading continued to bombard with trebuchets, and the Mongolian army, which had lost a large number of siege equipment operators, lost the ability to fight back, so they had to retreat the camp and let the Jiading army destroy all the siege equipment they left in place.

One night in mid-February, the Mongol army besieging the city of Jiading suddenly retreated quietly. In fact, there were signs of the retreat of the Mongol army, and the Mongol camp began to be busy a few days ago, and Yu Xing judged that the Mongols might be preparing for a new offensive. The Mongol navy was also extremely fierce during this time, and had organized an attack two days earlier, but suddenly left the battlefield in the advantageous situation and went straight upstream in the direction of Meizhou, leaving no sampans and boats on the water surface of Jiading. The next was the cavalry of the Mongol Yelumai Pillar who suddenly disappeared, along with the cavalry of Wang Dechen's department.

Looking at the empty camp of the Mongols, Yu Xing even hesitated. Pursue it, and I am afraid that this is a trick of the Mongols, so I specially lured the Jiading army away from Fort Li, a fort in Jiancheng. If you don't chase it, he really doesn't want to give up the chance to win. There are not many Mongolian troops killed this time, how can they win military merits? Compared with Yu Xing's calmness, the pursuit of his generals is much more eager. Some of these generals followed Yu Xing for nearly ten years, and repeatedly thwarted the siege of Jiading by the Mongol army, and gradually rose through the ranks. In their eyes, the Mongolian cavalry could neither catch up nor beat, although Wang Dechen's Mongol Han army could catch up but could not be defeated, but it was always possible to exchange the heads of the newly attached army of Yang Dayuan's department for military merits.

Yu Xing's heart was entangled, but he couldn't help the generals under him. Although he was a local emperor, he did not dare to ignore the interests of his generals. The so-called "cutting off people's money is like killing their parents", these people lick their blood with knives, that is, they want to exchange military merits for power and wealth. In the eyes of these generals, the opportunity to beat the water dogs obviously cannot be missed. Under the strong request of his subordinates to fight, Yu Xing hesitated for a long time and finally ordered the pursuit. However, he did not throw the main force in the direction of Longzhou, where the Mongol army retreated, but ordered to march to Meizhou, and it was only a partial division that pursued the new annexed army of Yang Dayuan's department. Although Yu Xing's character is despised, he is undoubtedly a capable person, otherwise he would not have defeated the Mongolian army in the cruel tug-of-war between the Song and Mongolian armies and besieged Jiading several times, and kept this most important city in western Sichuan. This order of his pursuit averted a catastrophic defeat and saved the lives of countless soldiers.

The partial division that was pursuing in the direction of Longzhou was ambushed by the Mongols and suffered a great defeat without surprise. This detachment relied on the terrain to be familiar and traveled lightly, and soon caught up with Yang Dayuan's department. To the surprise of the Jiading army, Yang Dayuan's troops did not flee in all directions, but met them without fear. The new annexed army of Yang Dayuan's department was originally the elite of the Song army, and it was also quite famous among the Song army in Sichuan. Just when the two sides were fighting inseparably, the Mongolian cavalry, which had not been seen for a few days before, suddenly appeared on the battlefield again, outflanked the Jiading army from both flanks, and rushed the Jiading army to pieces in an instant. Fortunately, the battlefield was surrounded by hills and low mountains, and the cavalry could not catch up, and the Jiading army was familiar with the terrain and hid in the forest and grass, so that the whole army was avoided.

Yu Xingqin led the main force to Meizhou, but was also returned by the Mongols, and Yelumaizhu's cavalry was already waiting there. It's just that Yu Xing is old enough to be prepared. This time, he led his army north to advance by land and water, and the infantry army accompanied the ships along the river. This kind of marching route allows the infantry army and the naval army to support each other, and although the speed is not comparable to taking the official road, it is also the safest. In addition, Yu Xing's purpose was only to recover Meizhou, and he did not seize time, so he adopted a steady and steady tactic. Under the cover of naval fire, the Jiading army calmly formed a formation in the face of the Mongol cavalry raid, and there were ships to protect their backs. The Jiading army even killed and wounded many cavalry and horses with strong crossbows. Seeing that there was no gap to take advantage of, Jerumaizhu had to retreat.

Before Yu Xing led the army to the city of Meizhou, he led his troops to hurry back. On the one hand, Liu Heima re-sent the naval army from Chengdu to reinforce Meizhou City. The Jiading naval army, which attacked against the water, had no advantage in the face of the Mongolian naval army with its back to Meizhou City. On the other hand, there was an urgent report from Jiading City, and a large number of Mongolian cavalry appeared under the city. At this moment, the strength of Jiading City is empty, and the main force defending the city is the people of the temporary organization, and the problem of holding the city in the short term is not big, but it is difficult to hold it for a long time.

After Yu Xing led his army back to Jiading, the Mongol army retreated. At this time, no one mentioned the topic of pursuit, but said: "Poor Kou Mo chase". In fact, the Mongol army did not lose many men and horses in the attack on Jiading, on the other hand, the Jiading army suffered very heavy losses. In addition to the fiasco of pursuing Yang Dayuan's partial division, the fall of Meizhou City in the early stage also lost a lot of soldiers.