After the Perak army occupied Guankou Village, they immediately cut off the connection between the Mongolian army in Chengdu and Weimao Prefecture, and Liu Heima naturally refused to agree. It's just that the Thunderbolt army has strengthened the wall of Guankou Village, and it is supported by the fire of naval artillery and warships, and the Mongolian army is not to mention attacking Guankou Village, even if the rangers get closer, they will be fiercely bombarded. Liu Heima had no choice but to adopt the tactics of using forts to control forts, built a fortress five miles east of Guankou Village, and sent a hundred Mongolian cavalry and 500 new annexed troops to be stationed here, harassing and attacking the Thunderbolt army and waiting for an opportunity to open the road into Weimao and Weimao.

This tactic of the Mongolian army initially caused a great headache for Guan Kou Zhai. These Mongol cavalry were like buzzing gadflys, making people's nerves tense at all times, and they couldn't sleep well at night. Chase and can't catch up, and the shelling hit rate is poor. In other words, there is not much ammunition in Guankouzhai, and there is really no room for waste. In response to this situation, Yu Zhu asked Ouyang Xuan and sent the cavalry battalion of the field brigade over to mount the cavalry. Although the cavalry of the Perak Army was far inferior to the Mongolian cavalry in riding and archery, they were equipped with firearms, and the ratio of battle losses between the two sides was about the same. However, the number of cavalry of the Perak army was several times that of the Mongolian cavalry, so after some fighting, the cavalry of the Perak army suppressed the Mongolian cavalry in the camp and did not dare to come out, and even used the tactics of hitting and running, frequently bombarding the Mongolian army camp with cavalry cannons.

"Exchanging the way of others for their bodies", the guerrilla tactics of the cavalry of the Perak Army made the Mongolian army miserable. They had to hold the camp during the day and go out of the camp at night, extending the trenches outside the camp to the periphery and digging a large number of trenches. This method was effective, and the number of Thunderbolt cavalry raids on the forts was greatly reduced. This ditch restriction cavalry is the first use of the Thunderbolt Army of Guankou Village, but Guankou Village is located on the side of the mountain, the soil is hard and it is not easy to dig a ditch, the number and density of trenches are insufficient, and the Mongolian army is skilled in horsemanship, so the effect is limited. The Mongolian army camp is located on the plain, which was originally fertile and loose farmland, and it is extremely easy to dig up the soil, and the criss-crossing around the camp will be dug in a short time.

After the Battle of Jiading, the cavalry of Yelumai's department returned to Chengdu, and Liu Heima sent 300 cavalry to the direction of Guankou Village. These 300 cavalry, together with the original cavalry, although the number was about the same as that of the Thunderbolt cavalry, but the combat power was superior to the Thunderbolt cavalry, so the initiative on the battlefield fell into the hands of the Mongolian army. Although the Mongol cavalry suppressed the Perak cavalry, they did not dare to approach within two miles of Guankou Village - if the number was small, they would be attacked and killed by the Perak cavalry, and if there were more people, they would be shelled.

The suppressed Perak cavalry also took advantage of the gap to attack the Mongolian camp, still using small artillery bombardment and running tactics. It's just that unlike the previous unscathed, this time many people were killed and wounded, and more than ten horses were lost. These casualties were caused by the use of new ammunition by the Mongolian trebuchet. Previously, the Mongol trebuchets fired stones, and the hit rate was very low, and they could not hit the fast-moving cavalry at all. In the Battle of Jiading, the Mongol army was heavily killed and wounded by grenades fired by the defenders from trebuchets, so they were also reloaded with new ammunition. The Mongols used two types of ammunition, an iron melon bullet containing gunpowder and a clay pot filled with an unknown liquid. Although the lethality of these two munitions is not comparable to that of Thunderbolt firearms, it is superior to the larger killing range. The Thunderbolt cavalry, whose speed was limited by the trenches, was killed and wounded by these two weapons. After getting the news, Ouyang Xuan ordered people to figure out these two weapons, and at the same time returned the cavalry battalion to be stationed in the Qiongzhou Field Brigade. The horses of the Thunderbolt Army are not easy to come by, and it takes even more time to train elite cavalry, which really cannot withstand this kind of attrition.

The Mongol cavalry saw that the Perak cavalry was no longer fighting head-on, and that there was no way to take the Guankou Village, so they went to attack the Perak checkpoint two miles away from the wall. As long as this level is broken, the road to Weimao and Weimao can be opened. The Perak army built two walls here, the first of which was made of waist-thick logs, and the second of which was made of stone and cement, but only half of them were built and it will take some time to complete.

Due to the small size of the checkpoint, the Thunderbolts guarding it only had a platoon, and because the wooden fence could not withstand the weight and recoil of the fortress guns, they were not equipped with artillery, but only muskets and grenades. Yu Zhu was not worried about the safety of this level before, in his opinion, the Mongolian army must use siege equipment to break through the fence, but before the Mongolian army can assemble it in front of the checkpoint, the fortress cannon of Guan Kou Village will make these siege equipment become parts. Although it is not easy for the fortress cannon to hit the personnel at a distance of two miles, it is not difficult to hit the huge siege equipment. Therefore, the Mongolian army tried to seize the checkpoint by sneak attack before, but the Perak soldiers guarding the checkpoint were very vigilant. The Mongolian army's sneak attacks each time left behind more than a dozen corpses and had to retreat in disarray.

Only two days ago, the checkpoint almost fell into the hands of the Mongols. In the morning of the same day, the Mongolian cavalry set out again and called for battle three miles in front of Guankou Village. During this period of time, the Mongol cavalry did not know that the Thunderbolt cavalry had withdrawn, but did not dare to confront it head-on, so they went to the village every day to provoke and scold. The foul language made the Perak soldiers furious, and they asked Shi Zhongshu, the commander of the garrison brigade sitting in Guan Kou Village, to open fire. Shi Zhongshu was unmoved, but just asked the Thunderbolt soldiers to scold back. Brother Xuan said that before the new arsenal is put into production, ammunition must be used sparingly. As one of the veterans of the Thunderbolt Army, Shi Zhongshu admired Ouyang Xuan so much. He witnessed Brother Xuan'er develop a deserted and fleeing grain collection squad into today's strong Thunderbolt Army, and he also became a battalion commander from a militia leader in Liuliba, and he felt so deeply.

Just as Shi Zhongshu sighed, he caught a glimpse of a cavalry team of fifty people hurrying towards the checkpoint, but he was not worried about this and did not give the order to shell the front of the checkpoint. In his opinion, these cavalry were just harassing again. It's just that these cavalrymen didn't stop in front of the checkpoint and scolded, but rushed straight to the gate. After rushing to the arrow, some of the Mongol cavalry fired arrows to cover it, while the other continued to charge forward, and all of them carried two horses, each carrying a package on their empty horses. The Perak soldiers guarding the checkpoint were not alarmed, their faces were calm, and they dodged arrows behind the fence, ready to wait for the Mongolian cavalry to rush closer before attacking them.

Only two-thirds of the 30 Mongol soldiers rushed to the gate under musket and grenade fire. Instead of throwing a rope hook and pulling the rope over the fence, as they had done before, they took out two kinds of balls, one black and one white—black and iron, and white pottery—from the package that followed the empty horse, and threw them at the defenders on the fence. Under the fire of the defenders, some of the balls were thrown over the fence, and some fell to the ground as the Mongols were shot. The spheres, both on the fence and on the ground, exploded, and the explosion ignited a raging fire.

Just as the cavalry was storming the checkpoint, a large group of new annexes came in line from the direction of the Mongolian barracks. When the level explodes, Shi Zhongshu senses that something is wrong. Now it seems that the Mongolian cavalry is obviously going to raid the checkpoint, the cavalry outside the wall is here to block the gate, and the new annex army is preparing to take the checkpoint and station. Fortunately, after a series of explosions, the direction of the level gradually fell silent. It seems that despite the heavy losses, the Thunderbolts held the checkpoint.