Because the armor and weapons to be built are the simplest, there is naturally no problem for Du Wu's current level of building. She drew all the drawings overnight, and came to the palace construction field in Nanzhao City early the next morning.

This building field was also built temporarily, because Nanban originally had no talents who knew how to build, and ore was even more scarce, and this industry was almost a blank.

The building field is an empty square, with a hundred iron furnaces built and anvils and hammers next to them. A simple canopy was added to the iron stove, because it was humid and rainy in Nanban, so the canopy was indispensable.

All kinds of materials from Zhongzhou State are piled up on one side of the square, ready to be used at any time.

The blacksmiths who came to support also came to the square early in the morning, waiting for Du Wu to arrange construction tasks for them.

After discussing with his mother, the four elders, and the generals of the Southern Barbarian Kingdom, Du Wu believed that the most urgent thing to build was a batch of arrows.

Because the black barbarians' best offensive technique is the magic of witchcraft, and they will drive some poisonous insects and beasts to assist. The most effective way to deal with them is to keep them from approaching. Bows and arrows are the most effective means of attack.

In the past, the flower barbarians also used bows and arrows, and there was no shortage of soldiers with strong archery skills. It's just that their bows and arrows are a bit shabby, and very few people's arrows can be loaded with metal clusters. Because metal is scarce in the Southern Barbarian Country. As a result, only some generals' bows and arrows could be equipped with metal arrows. Arrows used by ordinary soldiers are often made by sharpening bamboo. This type of arrow has poor penetration, and if the enemy is wearing the most ordinary rattan armor, the arrow will be difficult to break. Therefore, these bows and arrows need to be shot at the exposed parts of the human body to cause damage, which requires extremely high archery skills of the archers.

It is precisely because of this that as soon as Du Wu arrived at the palace construction site, he immediately posted the drawings for the majority of blacksmiths to see, and then immediately began to build. The first quest to craft is a million arrows.

At present, the Hua Barbarian Clan has a total of 100,000 soldiers, of which about 20,000 are good at archery. Du Wu wanted to equip each person with at least fifty arrows first, because arrows are consumable things and will gradually wear out, so the more the better.

The blacksmiths sent by Zhongzhou State are of different levels, but for the work of making arrows, it is not a problem, Du Wu has drawn the drawings again, and the length, weight, and materials of the arrows are clearly marked, so everyone has no problem building them.

In one day's work, 10,000 arrows were produced from these 100 blacksmith furnaces. Du Wu asked Niang to send someone to take it and test it for the archers in the army, because these arrows were somewhat different from the previous arrows in terms of structure and weight, so the soldiers needed to adapt.

Du Wu was not idle on this day, in addition to supervising the quality of the blacksmiths, she also opened the furnace herself to build a giant ballista machine.

Her plan is to build a hundred giant ballista machines, which will be as big as a warrior's spear, and can inflict great damage on enemy beasts and skilled warriors.

Du Wu had never built this kind of giant crossbow before, and this kind of giant crossbow was recorded in the booklet left by Wu Kesong to Du Wu, and it was extremely effective for the two armies to fight, and it could be worth thousands of troops.

Du Wu began to build according to the drawings left by the master, because there were many blacksmiths from Zhongzhou to support this time, and Du Wu selected ten people with better skills to build with her. She took the ten blacksmiths, each of whom was responsible for crafting a few parts of the giant crossbow and assembling them. This increases the efficiency of the work, and for each person, it is possible to become proficient quickly even if they only build a few parts.

After a day's work, Du Wu and the others had built all the parts of a giant crossbow and assembled them, and Du Wu made minor adjustments to the inappropriate places.