The tribes were disappointed that they could not buy firearms. Seeing this, Yang Wen told them another good news: although they could not buy firearms for the time being, they could buy a large number of well-made knives, swords, spearheads and arrowheads from the Thunderbolt Army, and even customize related weapons. It is said that although Miao Jiang can also make weapons, they are all hammered out by the small blacksmith's furnace, the quality is different, the output is low, and the cost is also high. This led to the tribal soldiers, who were only armed with iron weapons, and the improvised tribal militia could only use farm implements or even wooden sticks.

Cold weapons are low-tech, relatively simple to make, and have plenty of high-quality iron, allowing the Thunderbolts to be mass-produced. The advantages of industrial production are high labor efficiency, large output, stable quality, and the most important thing is that the price is not high, which is suitable for large-scale equipment. The Thunderbolts will also buy military weapons from Banju – crossbows and poisons. The crossbow thunderbolt can also be manufactured, but it is less needed, and it has to be made by hand, and the manufacturing cost is high, so it is better to buy it directly. Poison is a specialty of Miaojiang, which can be used in special operations such as reconnaissance and sneak attacks with military crossbows.

In the layout of the Thunderbolt Army, the arms trade is only a small part of the trilateral economic cooperation agreement. After repeated consultations between the three parties, the economic cooperation agreement reached has four parts. The first part is day-to-day trade, i.e. the exchange of goods between the two sides. The Perak army would export salt, ironware, and other industrial products to Miaojiang, which would exchange large livestock such as dwarf horses and buffaloes, as well as special products such as paint and tung oil, and the shortfall would be offset with gold and silver.

The goods that the Perak Army chose to sell were carefully selected, which was not only highly profitable, but also what Miao Jiang urgently needed. Although Miaojiang has a wide area, it has many mountains and narrow land, barren land, a few sloping lands with many stones, very fragmented cultivated land, and a lack of iron farm tools, so the grain output is very limited. Food scarcity has led to slow population growth, and inter-clan conflicts over land resources are often the case. The iron tools and farm implements of the Perak Army were well-made, and the raw materials used were from blast furnaces, and even better than those produced in Banshu. In addition, there is a tool that allows the old and weak and women to cultivate the mountainous land, the treadmill, which will greatly increase the grain harvest of the tribes.

As for the salt, it will be welcomed by the people. There is only sporadic salt production in Miaojiang, and most of the salt of the people comes from the Zigong Salt Prison in Chongqing and Luzhou. The cavalry of the Mongolian army came and went like the wind, frequently plundering the land in central Sichuan, and focusing on robbing and killing the living mouths to destroy the war potential of the Song army, and the well salt producing areas in Luzhou and Chongqing were the key targets. At present, these salt-producing facilities are either burned or not left. In addition, the government expropriated and corrupted officials to fill their own pockets, and the bandits were rampant along the way, and the price of salt transported to Banzhou was also very high, and then transferred to all parts of Miaojiang, the price was even more frightening, and ordinary mountain people could not afford to eat salt at all.

People can't eat salt for a long time, just like the people on the grassland can't eat tea for a long time, and the consequences are very serious. It will not only reduce appetite and make people weak, but also reduce the ability to resist diseases and weaken the combat effectiveness of the army. Because of its strong combat power, the Banzhou army was quite relied on by the imperial court, so although the salt under its rule was expensive, it could barely bear it. The tribes in Miaojiang are suffering from a lack of salt, and some remote tribes even have the situation that the whole village and village cannot eat salt. Being able to buy salt from Banju is one of the reasons why they are willing to obey the Yang family.

The salt production area of the Perak Army is in Qiongzhou, which seems to be much farther away than Luzhou and Chongqing, but because it is by water, and there are fewer kinds of exploitation, the cost of transportation to Banzhou is not high. After Zhu Xuanzi's calculations, the price of transportation to Banzhou and reasonable profits was only one-fifth of the current official salt, and even if it was transported to the main villages of various tribes, the price was only one-third. The price, while still expensive for poor mountain dwellers, is at least affordable.

Economic and trade relations are to be sustainable for a long time, and they are naturally voluntary and reciprocal. The Thunderbolts sold goods such as salt and iron, and also needed to buy things to balance the trade. However, among the items sold by Miao Jiang, large livestock such as ponies and buffaloes are important means of production, and even if the tribes are willing to sell them all, the Perak army will not do this kind of thing. Tung oil is a good thing, not only for shipbuilding, but also for making firearms, but the demand is not large, and the same paint, bristles and other materials are not in demand. Fortunately, Miaojiang is rich in gold and silver, and there are small-scale mines in many places, and gold can also be found in the river, which can be used by various tribes to make up for the lack of exchange materials.

The second element of the economic agreement is the opening of mines and factories. The Perak Army was thousands of miles away from Banzhou, and it took ten days and a half months to take the low-cost waterway. If you go to the Luo clan ghost country and other tribes around Banzhou, you will need to travel hundreds of miles. Most of these roads are mountainous, and some sections are very difficult to navigate. If all the goods were transported from western Sichuan, not to mention the long time spent on the road, it would be easy to be blocked due to war and other reasons, so the Perak army decided to cooperate with Banju and other tribes to open mines and build factories on the spot. To be precise, it is to cooperate with various tribes to open mines, and with the Banzhou Yang clan, it is to open mines and build factories.

Miaojiang is rich in resources, with many coal and iron ores, mercury ore resources, and many lead-zinc ores and nitrate ores. In the early stage, the Perak Army technicians, accompanied by the Banju side, explored in detail the addresses suitable for mining and factory construction. According to the plan, the mines were financed and skilled by the Perak Army, and the tribes financed with resources and manpower, mainly for gold, silver, mercury and nitrate, while coal and iron were mined in convenient places within Banju for easy transportation to the neighboring industrial areas. The first phase of the industrial zone, which is located near Hailongtun and is difficult to defend, includes a coking coal plant, a steel plant and a foundry for the production of cold weapons and agricultural tools.

The third content of the economic agreement is the development of trade routes and the establishment of trading bases. Yang Wen told the chiefs that only by opening up the business road to the distance and transporting more urgently needed resources can the life of the people of Miaojiang be better. Of course, the Hao chiefs understood this truth, and they did not want to be poor, so they naturally supported the idea of extending the trade route through the jurisdiction of their tribe to the coast and Dali. In fact, they also knew that there were more good things in the distance, such as the Dali Kingdom bordering the Luo Ghost Country, which was rich in a large amount of copper, which was second only to gold and silver, and could make copper gongs and copper drums, the two most important ritual utensils of the tribe.

Naturally, the tribes also supported the Thunderbolts in establishing trading posts on trade routes. According to the plan, the Thunderbolts would establish a series of strongholds on the two main trade routes leading to the coast and Dali. Each of these strongholds was fifty miles apart and was built in the cottages of the various tribes. In order to improve the level of education and health in the local area, in addition to two caravan members, each trading post will also be equipped with a Lang Zhong and a teacher to teach students and treat the mountain people free of charge. In fact, the two caravan members were also Thunderbolt intelligence collectors.

Ouyang Xuan and Yang Wen both know very well that the relationship formed by interests is the strongest. Therefore, the last clause of the economic agreement is the sharing of interests. According to the agreement, the proceeds of mining will be divided between the Thunderbolt Army and the party where the mine is located; The factory's revenue is split between the Perak Army and Banju; Perak and Banju will establish a joint caravanserais, and will use one-fifth of the caravanserais' profits in Miaojiang to build roads, bridges, and medical education for the various tribes.