Ouyang Xuan knew that Yu Xing would not be satisfied, and in the future, he would definitely intensify his efforts to secretly stumble on the Thunderbolt Army, and the most likely thing was to cut off the Thunderbolt Army's fleet to and from Banzhou. In this regard, he has made two preparations, one is to ask Yang Yan to replace all the sailors of the Nanyang Company in charge of this line with the Banzhou people's clan, and hang the banner of the Banzhou Yang clan. If Yu Xing wanted to seize the merchant ship, he asked his father-in-law Yang Wen to negotiate with him. The second is to open up a water and land transport channel from Luzhou to Banzhou City. This route is actually hundreds of miles closer than the water route through Chongqing and Fuzhou, but it is not easy to reach Banzhou City directly from Luzhou through the Chishui River, and it is not easy to walk on a hundred miles of mountain roads to transport heavy goods such as bulk commodities and artillery.

After Yu Xing's envoy left, Ouyang Xuan completely put the matter aside, because he now had more important things - to take Chengdu City and expel the Mongolian army from western Sichuan. Since 1242, the Mongol army has invaded Shu in all wars, and the city of Chengdu has been slaughtered several times, and the prosperity of a million people is long gone, and the city defense is also dilapidated. However, because it is located in the center of the West Sichuan Plain, the strategic location is extremely important, so it has become the core city of the Mongolian army to run the west of Sichuan. Taking Chengdu means that the Thunderbolt army will occupy the fertile western Sichuan Plain, laying the foundation for the next step of expelling the Mongol forces from Sichuan.

The army generally had to rest after the end of the war, on the one hand, to allow the soldiers to get enough rest, and on the other hand, to replenish the food and grass equipment. At this time, not long after the end of the Battle of Jiading, the choice to attack Chengdu seemed hasty, but in fact, Ouyang Xuan made a careful decision after careful consideration. Before the Battle of Jiading, he ordered the General Staff to draw up an operational plan, and also ordered the military and logistics departments to make corresponding preparations. Even half a year ago, the special brigade, the navy brigade, the teaching brigade, and the caravan were planning reconnaissance matters, and sent a large number of reconnaissance teams to Chengdu, Hanzhou, Gendingcheng, Huaizhou, and other places, bringing back a large amount of information on the Mongolian army's garrisons, grain, and grass, and drawing up maps of the march routes. Therefore, after the end of the Jiading Campaign, the military-political joint conference quickly agreed on matters related to the operation.

Ouyang Xuan believes that the current is the best time to attack Chengdu, based on the following judgments. From a political point of view, due to the struggle of the two Mongol khans, there was no time to attack the Han land on a large scale, but the Southern Song court, which had a chance to breathe, did not take the opportunity to reorganize the army and war, but instead sued for peace with foreign reparations, and began to persecute Zhongliang internally, playing the trick of "rabbit dead dog cooking". After Kublai Khan led his army from Ezhou to Kaiping, Jia Rudao boasted that he had repelled it, and the mediocre Song Lizong believed it and believed that it had the merit of reinvention and entrusted him with the power of the court. After Jia Yidao took sole power, he began to snard charges against political opponents, and the famous generals Xiang Shibi and Cao Shixiong were imprisoned just because they were disrespectful to them. The Perak Army's attack on Chengdu showed its opposition to reparations and peace, and military action would inevitably cause retaliation from the Mongolian army in Sichuan and even the Mongolian army in Jinghu and Lianghuai. When the war is tense, the persecution of loyal ministers and good generals by Jia Rudao and others will also be reined in.

From the military level, the dispute between the two khans made the Mongolian soldiers in Sichuan panic, and the current secret Huoli and Qitai Buhua were killed, and Niu Ling was also released to Kaiping, and the remaining Mongolian troops were suspicious of each other, and the coordination was not as good as before. Since the main battlefield between Kublai Khan and Ali Buge was in the Mongolian steppe and Qinlong region, Kublai Khan, who initially mastered Sichuan, sent a large number of Mongolian cavalry north to Qinlong, which greatly reduced the strength of the Mongolian army in Sichuan. Although there are still about 15,000 people in the Sichuan Ximeng army, most of the new annex troops with low combat strength are only the Kudu Department and Liu Heima Department. The former had a thousand Mongol cavalry, while the latter's Mongol Han army had a thousand cavalry and two thousand infantry.

On the other hand, at present, there are more than 10,000 people in the Perak Army, and in addition to the personnel left behind, field divisions, special brigades, teaching brigades, and naval brigades can be dispatched, totaling 9,000 regular troops, and tens of thousands of basic militiamen who are responsible for logistics and baggage, plus Jiading Zhan Wanshou can also dispatch 2,000 people, the number has exceeded that of the Mongolian army, and the firepower projection capacity is several times that of the Mongolian army. At present, the Sichuan Ximeng army can fight against the Thunderbolt army, only the 4,000 people of Kudu and Liu Heima, as for the new annex army, the combat strength is not as good as the basic militia of the Thunderbolt army. More importantly, it was the rising season in July, and the water surface of the large and small rivers in western Sichuan was wide, which was very conducive to the warship operations of the Perak army.

Economically speaking, the population of Chongqing and Qiongzhou has reached as much as 500,000, and more than 3 million acres of fertile land. If we add Meizhou and Yazhou, which have just been recovered, the population has reached more than 700,000 people, and the number of acres of land has reached more than 6 million mu, and the dispatch of more than 20,000 people to fight will not have a major impact on economic activities, and grain will also be fully guaranteed. On the other hand, in western Sichuan, which was occupied by the Mongol army, although the area of cultivated land was larger, due to its blind exploitation and expropriation, the population was less than 150,000, and there was no surplus grain at all. More importantly, in addition to the two most important indicators, population and food, the Thunderbolt Army also has an industrial production capacity that makes the Mongolian army feel terrified, and the war potential is several notches higher.

From a tactical point of view, the current Mongolian army in western Sichuan is stationed in the counties under Chengdu Prefecture and Hanzhou, Pengzhou, Mianzhou, Jianzhou, Longzhou and other places, and the troops are scattered and lack effective coordination and command. Since the naval army trained by Liu Heima has been completely disabled, the Mongolian army cannot use the dense rivers in western Sichuan to maneuver, and can only rely on the 2,000 cavalry to maneuver, but the Perak army also has a cavalry brigade, which will offset its advantage. In this hot summer season, the horses produced by the Perak army from the Tibetan region and Dali have an advantage over the Mongolian horses from the Mobei grassland. In this way, the Thunderbolt army can concentrate its superior forces, capture Chengdu with lightning speed, and then break through the rest of the states and counties one by one, and even make a decision.

This attack on Chengdu will be the elite of the Thunderbolt army's infantry, cavalry, and water armies, and it is not an exaggeration to say that it is a battle of life and death. "The war is fought on the economy and logistics", for this reason, under the coordination of Ouyang Xuan, the whole Thunderbolt army is going all out for this battle. In terms of food, in addition to sufficient marching rations, Li Shuang ordered the killing of hundreds of pigs and old, weak, sick and disabled horses and cattle, salted with smoke and salted and distributed to each soldier, so as to ensure physical strength under high-intensity combat. For war horses and mules and horses transporting heavy cannons, concentrates such as fried soybeans and broad beans began to be added. In order to lighten the burden on the soldiers, Huang Dagen requisitioned and modified a large number of civilian boats, especially light boats, to transport them through a dense network of rivers. During the rainy season, it becomes extremely difficult to walk on the road if it rains continuously.

War is full of surprises, and bad weather is especially important for the Thunderbolts, whose main combat power is firearms. Due to the extensive use of mercury fuses, the Thunderbolt Army's grenades and mines do not need to be ignited when they are used, and they are also wrapped in oiled paper and tarpaulin, so there is no big problem with waterproofing. However, due to the lack of copper, most of the musket bullets used today are paper shells, and the artillery powder bags are sealed with silk cloth. Although these munitions were also sealed with tarpaulins, they were easily soaked with water in heavy rain. Although heavy rain could also wet the bowstring and severely affect the Mongol cavalry, the Mongol cavalry could abandon their bows and use their rifles to charge into battle. In order to prevent this from happening, Cao Ergou prepared a lot of anti-cavalry weapons and tools while ordering the increase of waterproof equipment.

Preparations for war were in full swing, and the technical details of the battle were also raised in the sand table and solved one by one. By the end of July, preparations for the attack on Chengdu had been prepared, just waiting for Ouyang Xuan's order.