The seven subordinate tribes all needed copper weapons, copper spears and copper axes in half, and only the Japanese tribe exchanged ten rattan armor and thirty rattan shields.

Only half of the twenty-six bronze weapons exchanged for the fifty-eight captives belonged to the Japanese tribe, and together with the eight bronze weapons exchanged for animal skins, the Japanese tribe finally exchanged for a total of ten rattan armor, thirty rattan shields, five copper spears, and five copper axes.

The clansmen from the seven affiliated tribes were a little puzzled, and they didn't know why the Japanese tribe wanted to exchange for the rattan shield and rattan armor that each tribe had, wasn't it a waste.

They didn't say this, they were just members of the subordinate tribe, and they were not qualified to get involved in the affairs of the main tribe.

In the end, the Japanese tribal camp exchanged a total of 118 bronze weapons, 10 rattan armors, and 30 rattan shields, which the second trading fleet could directly take out.

The deal was reached, the second trade fleet was about to return, and before leaving, Zhao Lin Yingxi gave each of the seven affiliated tribes a rattan armor and a rattan shield, and the bronze sword was not sent.

The second trade fleet left, and the Japanese tribe hurriedly sent a team to send the food needed by the front-line army and the weapons and equipment that had just been traded to the front line.

……

The second trade fleet returned, the first trade fleet set sail, and the dragon tribe returned to normal life.

As the two trading fleets traveled between the banks of the Yellow River to trade with many tribes, there were more and more animal skins in the Dragon Tribe, and Su Yan's concern for animal skin tanning made breakthroughs.

The most important role of animal skin tanning is to make leather armor.

Rattan armor is the most common armor in this era, after all, the material used to make rattan armor is very simple, just rattan that can be seen everywhere, and most tribes will use rattan to weave rattan shields and even rattan armor as defensive equipment to protect themselves.

However, the shortcomings of the rattan armor are also very obvious, the initial rattan armor defense is not good enough, even the dragon tribe's rattan armor can only resist a heavy attack, if the second heavy blow hits the position of the previous blow, the person wearing the rattan armor will be directly seriously injured.

The use of rattan armor is not long, after all, it is only a rattan product, if the rattan armor of other tribes is not damaged, it will be used for two years at most, and the defense of the rattan armor itself will be greatly reduced after two years, and the rattan armor of the dragon tribe can be used for about three to four years, and it is difficult to resist a heavy blow after this period.

There is also a rattan armor that is heavier, especially the dragon tribe's rattan armor that has gone through multiple processes, which has higher defense than the rattan armor of other tribes, but it is also heavier, so that the rattan armor soldiers of the dragon tribe can only carry lighter rattan shields, but cannot carry heavy and higher defensive copper shields.

Changing to leather armor, in the history of China, even if the (metal) armor with higher defensive power appeared, leather armor still occupies a very important position, mainly because leather armor has a certain defensive power, and it is lighter and cheaper than armor, as for rattan armor, there is almost no reputation.

It's not that the defense of rattan armor can't catch up with leather armor, with the development of rattan armor technology, the defense of rattan armor in the later period is not worse than leather armor, and the weight is not as good as armor.

But the rattan armor production cycle is a hard injury, longer than the armor production cycle, it is better to use leather armor or armor, the rattan armor that appeared in the same era will only be those rattan armor with a short production cycle and relatively cheap, and the defense is not enough, so it does not have much reputation.

With the conditions of the dragon tribe, it is difficult to make vine armor with higher defense, and there is no need for that, it is better to abandon the vine armor and develop leather armor, and when the dragon tribe has a large population, you can also use coal to smelt iron and develop iron armor, and the vine armor is slowly eliminated from the dragon tribe, at most it is used to trade with other tribes.

The key to making leather armor is to use animal skin to make tanning, tanning is a process of tanning raw hides into leather, removing the hair and non-collagen fibers of animal skins, etc., so that the collagen fibers in the dermis layer are moderately loose, fixed and strengthened, and then decorated (managed), and finally become leather.

Su Yan doesn't know much about the process of animal skin tanning, only knows the simple processes of "soaking in water, soaking in ash, hair removal, softening, pickling, and tanning", and the specific content is unknown.

Earlier, Su Yan organized a group of female tribesmen to continue to try to process the animal skin, and it took several years to tann the leather until now, but the nature of the first piece of leather tanned did not meet the standard of making leather armor, and even if the leather armor produced, it could not be compared with the rattan armor produced by the Dragon Tribe.

It was only when leather technology developed that leather could be used to make leather armor, and the first pieces of leather that were tanned could probably only be used to make leather clothes and shoes.

However, the leather has already been tanned, and a corresponding set of tanning animal skins has been recorded, waiting to be improved and improved.

The first step of tanning animal skin, soaking in water, this step has a great impact on the quality of leather, this step must be carried out seriously, the source of tanned animal skin is different, there are old skins that have been used for many years, and there are fresh animal skins just obtained, the purpose of soaking is to restore the raw material skin to the state of fresh skin, remove part of the capacitive protein, and remove blood, feces and other sundries, the older the animal skin soaking time.

The second step, shave, the soaking of the softened fur inside spread upwards on the half-log, with a bow knife scraping off the fat attached to the meat surface, residual meat, etc., in order not to hurt the hair roots, in the scraping can be spread on the log first a thick cloth, cutting and the next step of degreasing has a close relationship, if the residual fat is not conducive to degreasing, the role of scraping with a bow knife is also to squeeze the residual fat in the skin to the surface of the skin, which is conducive to degreasing.

The third step, degreasing and washing, the quality of the finished fur depends on whether the degreasing is thorough, in the degreasing process, the fat should be removed, and the fur is not damaged, the use of saponification method is more modest, the principle is the use of alkali (can use plant ash or slaked lime) and grease to generate soap performance, remove the oil on the coat, the degreased fur should be washed immediately, remove the soap liquid, wash and rinse, the skin is cool and dry.

The first three steps are all about the pre-tanning of the hides, and the fourth step is when the tanning of the hides really begins, and in this step you need to prepare another thing - tanning agent.

In human history, it has been found that the juice or mineral oil of some plants has a certain tanning property for leather, and the raw leather is more breathable and anti-corrosion through the soaking of the juice, so that the plate has softness, tear resistance, flex resistance and other physical and chemical properties, so that the leather really has the characteristics of leather products, and this juice is the tanning agent.

The tanning agent used by the dragon tribe is the sap of plants, such as the bark of the common mistletoe, oak, and spruce trees.

The treated hides are soaked in water with tanning agents, and the soaking time is more than seven days before the soaking is completed, and then the leather products are sorted out to complete the whole process of tanning the hides into leather.

The dragon tribe's rattan armor production period is up to half a month, compared with it, the tanning period is not much shorter, between the importance of leather products, the dragon tribe will focus on the development of tanning technology in the future, and the process of making rattan armor rattan shield can be suspended.