Most of the Koreans who surrendered voluntarily were guys like Kim Yoon, who had a good background, but were still just slaves.

They grew up in a family of Goryeo officials, and although they were not systematically educated, they were still more knowledgeable than the slaves and maids who were originally born at the lowest level.

For example, Jin Yun knew very well that there was a big difference between the Zhou people and the Japanese people - the former was more or less merciful than the latter, at least he would not kill people when he saw them, and he would not play killing as performance art.

Even, Jin Yun guessed that the senior officials of the Zhou people were better served than Goryeo's own two shifts.

It turned out that this was indeed the case, at least Xu Shiyang and the officials of Qi Province were indeed more harmonious than the two classes of Goryeo themselves.

Well, they also kill, and they kill prisoners proportionally, but after killing, the Qi soldiers usually rarely use their knives.

What's more, the rest of the captives were all accurately informed from the guards - after accumulating twenty merits for the Qi Province strugglers, they could be promoted from slaves to commoners, and if they accumulated ten more merits, they could be promoted from commoners to commoners.

Qi Province adheres to Xu Shiyang's policy of "having classes, but never blocking the upward channel", and in Qi Province, even slaves have the opportunity to become free people.

For this reason alone, Jin Yun believed that Qi was much stronger than Goryeo, and besides, Qi Province was not as subservient as Goryeo.

If a slave is promoted to commonerhood, then both his children and his biological parents will be qualified as commoners at the same time - because the traditional culture of the Han people does not allow parents to call their children masters, which is absolutely perverse.

There is a channel for rising, and it is already attractive enough for Goryeo officials and private slaves.

In order to set an example, Xu Shiyang also deliberately announced that the Goryeo people who surrendered voluntarily did not need to be slaves, and could directly start from the common people.

In Qi Province, the common people were composed of foreigners who surrendered voluntarily, slaves who had accumulated merit and promotion, and Han Chinese who had committed crimes but did not die for their crimes, and were a class between ordinary commoners and slaves.

This class was allowed a certain degree of personal liberty and personal property, but was subject to much heavier labor and tax rates than the common people.

When buying grain for official sale, the price is much more expensive than that of civilians, so it is difficult for them to enjoy the preferential treatment of cheap grain in Jiangnan.

It also suffers much more than civilians in terms of interest rates on loans and deposits.

However, the common people are always much better than slaves, and if they work hard or fight bravely, they can accumulate ten merits and become real common people.

In Jin Yun's view, the living standards of the common people of the Han people were already much better than those of the Chinese class in Goryeo, and when he thought that he had been freed from slavery status, and as long as he fought hard, he would have the opportunity to become a Chinese of the Great Zhou (he did not know the specific relationship between Qi Province and the Great Zhou), Jin Yun felt more and more that his initiative to surrender was the most correct choice.

Therefore, he became more and more eager to help the Han people conquer Goryeo.

At the foot of Manju Mountain, in the camp of the former enemy headquarters of the Qi army, Jin Yun took more than 10 Goryeo people who voluntarily surrendered to show Xu Shiyang, Li Feifeng and the officers of Qi Province the main weapons and usage of the Goryeo army.

What aroused Xu Shiyang's curiosity the most was naturally the kind of short arrow that had a long range, but was not powerful enough.

In fact, this kind of thing is not unusual, in the era of cold weapons, whether in the West or the East, many armies have been equipped with this kind of thing.

It is called a piece arrow, and it is a type of light arrow, which is only half the length of an ordinary feather arrow, and it is very light, so it is possible to shoot up to 400 steps away in a downwind state at a high place!

Also, due to the very short length of the arrows, they must be fired with a pipe, and even if the enemy captures or picks up them, they cannot be shot back with a normal bow.

Because of these advantages, the Goryeo people were particularly fond of the weapon of the Katakuji, which had a high proportion of Kakuchers and a very good archery skill in the more elite standing army (5 to 10 percent of the registered troops).

Of course, the shortcomings of the piece arrow are also very obvious - as a light arrow, the armor-piercing ability of the piece arrow is pathetic, and it is a very useful weapon to use against the Japanese who do not wear armor at all.

But when used against Tartar armor soldiers who like to charge in heavy armor, the piece of arrow is like a joke.

To make matters worse, the Goryeo army placed too much emphasis on the range of bows and arrows, and always hoped to be able to defeat the enemy with long-range shots, so that even self-defense weapons pursued rapid drawing of swords, so that the short sword of 1 foot 7 or 1 foot 6 inch became the most common equipment (the sword or waist knife, the length was around 3 or 4 feet).

Long-range shots do not pierce Tartar armor, and melee short knives are not the opponent of Tartar armor, so it is no wonder that every time the Jurchens invade, they beat the Goryeo Kingdom extremely embarrassed.

What's even worse is that the siege building skills of the Koreans are also amazingly poor.

It was a common situation in Goryeo to have a fortress like Manjusri Mountain Fortress, where there was not a single battlement, and soldiers stood on top of the bare city wall and were shot at by the other side from a distance.

Kim Yun himself was once requisitioned as a slave by the king of Goryeo to participate in the construction of Namhansanseong near Wangjing, which was built as the king's first choice for refuge in times of crisis.

However, Kim Yun confessed that there were still surprisingly few battlements in Namhansanseong, and Kim Yun himself had counted that there were less than a hundred battlements in Namhansanseong that could be used by soldiers to hide.

Moreover, the walls of Goryeo were all low walls that went straight up and down, and the earth behind them formed a slope for soldiers to go up and down the city.

There are no moats, moats, deer rocks and other ancillary fortifications outside all the walls, which means that even if the king of Goryeo built a shelter for himself, he can drive straight into the city by breaking through a low wall!

The Kingdom of Goryeo is really an overly easy target, and Xu Shiyang is even a little skeptical now, why didn't the Tartars eat the whole of Goryeo alive.

The main reason, it seems, is that Goryeo itself is very poor in land, and the occupation of these lands costs far less than the income that can be obtained.

Therefore, it is better to use Goryeo as an ATM, and grab it when you need it, and take away all the food, goods, and people you can take with you.

And once the Jurchen Tartars withdrew to Liaodong because the occupation was too much to lose, the king of Goryeo would either hide in the mountains or hide on the island, and he would return to Wangjing proudly and continue to be his own king of Goryeo.

Anyway, when the Tartars attacked, most of the people who were snatched and killed were still slaves and maids who were not human, and neither the king nor the two classes would feel sorry for it.

The problems encountered by the Tartars in Goryeo, Xu Shiyang will also encounter them.

That is, unless it is a guy like the Japanese who is even more miserable than the life of Goryeo, for others, the occupation of Goryeo is actually an act that outweighs the cost.

Then, the strategic goal of Xu Shiyang's expedition must be clearer: to plunder supplies and population, force Goryeo to submit, and become a link in the Jurchen encirclement network, but not to completely annex Goryeo.