Just as the Perak Army's top brass was dealing with the blockage of the Yazhou trade route, the northern route of the Ancient Tea Horse Road to Weimao was also facing increasing pressure from the Mongolian army. The checkpoint is two miles away from Guankou Village, and although this section of road is within the fire coverage of Guankou Village, it is not protected by low walls and trenches. Mongol rangers often attacked caravans as they passed through these two miles, but the frequency and counterattacks of the guards did not have much impact on the caravans. Recently, the frequency of attacks by the Mongolian army on this section of the road has increased significantly, and it has changed the strategy of traveling far away to send arrows in the past, but taking advantage of the gap in the loading of the cannon of Guankouzhai to rush into the caravan and slash and kill, although it has suffered heavy losses, it has also caused large casualties to the caravan personnel, and even burned a lot of goods with fire oil.

At first, the Thunderbolt Army was also puzzled by the Mongolian army's life-fighting style. The Mongol cavalry had always been known for its tactical agility, and now this style of fighting, regardless of casualties, was purely a vent of anger. Qian Laoer, who is in charge of the trade between the two states of Weimao, speculated that it may be related to the sharp increase in trading volume. Recently, due to the absence of Mongol restrictions, the trading volume between the Thunderbolts and the two states of Mauvai has increased several times. It's just that with the passing of the peak of trading, the current trading volume has returned to a normal level, but the intensity of the Mongolian army's attack has not decreased, and it is still this kind of fighting style of killing 1,000 enemies and losing 100 by one. Seeing that the Mongol army refused to stop, Shi Zhongshu had to organize people to start digging a trench from Guan Kou Village to the checkpoint, and applied to Li Shuang to transfer cement to build an additional wall next to the trench to protect the caravans.

In the current mature trade route of the Perak Army, the direction of Yazhou was cut off by Cao Zhizhou, and the waterway to Jiading was blocked due to shallow water and the water barrier of the Mongolian army, but the trade route of Weimao and Weimao was still unblocked. This was not only the most important trade route for the Perak Army, but also copper, nitrate, medicinal herbs, and meat, as well as pack animals and war horses. This is also the nearest trade route, Chongqing Fucheng to Maozhou is only more than 100 miles. The top brass of the Perak Army attached great importance to this trade route and ordered it to be defended no matter what. Therefore, in addition to agreeing to the invitation of Guan Kou Zhai, a cavalry company of the reconnaissance battalion of the Internal Guard Brigade was sent to support. Some of this cavalry company are Tibetan people who have been riding since childhood, and there are also soldiers of the former new annex army who are familiar with equestrianism, and their equestrianism is more skilled than that of the field battalion cavalry company, and they are more suitable for dealing with the Mongolian army rangers.

With the construction of trenches and walls, and the arrival of scout cavalry, it became almost impossible for the Mongols to attack the caravans. If you attack again, it is almost the same as suicide. The defense of the checkpoint has been strengthened a lot in recent times, so the Mongolian army has to return to its original state of shrinkage. It was only due to the small camp and the lack of grain and grass that the 300 cavalry of the Yelumai Pillar had to withdraw to Muma Mountain in Shuangliu County. Only the original new annexes and cavalry remained in the barracks. After this period of attrition, there were only more than 300 new troops of the 500 new annexes, and there were only more than 70 cavalry.

The reason why the Mongol army built the fortifications was, on the one hand, to trap and lock up the expansion of the Thunderbolt army, and on the other hand, to lure the Thunderbolt army to attack, and then use cavalry to outflank and encircle the siege, and defeat the Thunderbolt army in the field. It's just that Ouyang Xuan had already seen through the Mongols' plan to lure the snake out of the hole, and ordered Shi Zhongshu to hold out. Over time, the Mongols also saw that the Perak army had no interest in these camps.

In fact, the Thunderbolt army could adopt the method of defeating the Mongol army at Mingshan City, digging trenches and fortifications layer by layer, and bringing artillery close to the Mongol army camp. The reason why this was not done was that the Mongols had more than a dozen of these improvised barracks on the border of the areas controlled by the two sides, and the amount of artillery required to destroy these barracks was so large that it was not worth the cost of precious shells by the Perak army. In the battle of Yokohara Fort, the Mongol army found that the trench was a sharp weapon against artillery, so the Mongol army dug many trenches inside and outside the camp. Even if these barracks were destroyed, the casualties would be small, and they could be rebuilt a little back.

Just when the Mongolian army was paralyzed, the Thunderbolt army was mobilizing troops and horses, preparing to launch a thunderous blow. Ouyang Xuanzhi changed his mind to take the camp of the Mongolian army in Guankou Village, in addition to fighting its arrogance, so that the enemy could understand that the Thunderbolt army was not unable to capture these camps, but also to pull out this thorn stuck near the trade road. Although this thorn no longer poses a threat to the Tao, it is still a hidden danger. The Thunderbolts also learned from their captives that there was still a considerable amount of fire oil in the camp. This thing is too much of a threat to the Thunderbolt warships, and if it can destroy a little, it will be less. After all, even if the Mongols had many horses, it was extremely difficult to transport fire oil from far away West Asia.

What really made Ouyang Xuan decide to do it was the defection of the small leader of the Thunderbolt Army caravan. This small leader was originally a bookkeeper in Jiangyuan City, and was later recruited into the caravan by Qian Lao Er and was responsible for the financial accounting of the Weimao Trade Road. This person was also a conscientious person, but some time ago he made a private agreement with a Qiang woman in Weizhou for life, but he was opposed by the other party's parents. To say that the Perak Army encourages the freedom of marriage, but Willy is not the territory of the Perak Army, and the people still obey "the orders of their parents and the words of matchmakers". This woman has already been betrothed to the son of a large local family, although she is reluctant but helpless. The bookkeeper asked the woman to elope, but was caught and beaten by the locals and returned to the caravan. After the second generation of Qian lost money, he did not punish Mr. Ledger. Unexpectedly, the bookkeeper complained that the Perak army did not stand out for him, so he slipped out of Guankou Village at night and threw himself into the Mongolian army a few miles away.

Ouyang Xuan's goal in this battle, in addition to completely destroying the Mongolian army's barracks, also ordered to kill this traitor. In the early stage, it took a lot of trouble for the Thunderbolt army and the locals to quietly kill the Mongolian army in Weimao and Weimao Prefectures. Now that Liu Heima knows what happened in Weimao and Weimao, he will inevitably take revenge on the officials and people of the two states, and even slaughter the people of the two states. Although the Mongol army could not attack from the direction of Guankouzhai, it could enter Songzhou from the grassland area and attack the two states along the river valley. More importantly, after the Mongolian army learned from this traitor about the types of strategic materials required by the Thunderbolt Army, it would inevitably restrict or plunder these resources everywhere to stop the rapid development momentum of the Thunderbolt Army. "There are more than 100 people, all kinds of people", although Dong Hu's anti-spy personnel are shrewd and strong, they can't prevent these ghosts with different intentions. The crimes of traitors must be investigated in order to deter those who harbor dissenting intentions.

In order to achieve a one-hit kill against a traitor, it is necessary to fight quickly with absolute force and firepower. This was to prevent the traitors from escaping, and also to prevent the Mongol cavalry from coming to their aid. At present, the Thunderbolt army in Guankou Village is more than enough to defend but not enough to attack, and the gunboats of the navy cannot provide the opportunity to attack the Mongolian camp. Therefore, Ouyang Xuan used the main force of the Thunderbolt Army's land warfare, the Field Brigade.

In order to prevent the Mongol army from detecting abnormalities in the camp, the Perak army intensified its reconnaissance and attack, attacked and suppressed the Mongolian scout cavalry, and frequently attacked the Mongolian army camp with light artillery. After the two infantry battalions of the field brigade arrived from Qiongzhou, they did not rush into Guankou Village, but took advantage of the night to enter the village in batches and hide in the village. The cavalry battalion hid farther away, and after the artillery of the infantry battalion had been fired, it and the cavalry company of the reconnaissance battalion hurried back to the rear of the Mongolian barracks to intercept and kill the fleeing enemy.