At the beginning of June, Xiahou Yuan finally built a trebuchet, Cao Cao's trebuchet was indeed very large, but the stones thrown were not much larger.

Cao Cao's traditional thinking made him not pay attention to craftsmen. There is absolutely no problem for his craftsmen to work, after all, they rely on this ability to eat, but academically it is much worse.

Why? To give an example of "Romance of the Three Kingdoms", Zhuge Liang made wooden oxen and horses, and was robbed of several by Sima Yi, and then Sima Yi followed suit and made thousands of horses in half a month, and then Zhuge Liang used a trick to rob them back, and got thousands of wooden oxen and horses and the grain in them in vain.

Zhuge Liang used Sima Yi didn't understand the principle of making wooden oxen and flowing horses, so he made a small switch on it, which couldn't move after being pressed, and he could walk when he pulled it up. Sima Yi's craftsmen didn't know why it was before, and so did Cao Cao's craftsmen.

They will only build trebuchets according to drawings, or maybe not drawings, but words. After all, there are records of trebuchets from the Spring and Autumn Period and the Warring States Period, and there was no paper at that time, so drawings were not necessarily left.

They only know how to make it, but they don't know how to make the stones thrown by the trebuchet bigger or throw farther, which is the limitation of the craftsmen, who do not have enough theoretical knowledge and do not know the working principle of the trebuchet very thoroughly, and may not even understand the principle of the lever.

But there are too many people who can't stand Cao Cao! Cao Cao erected forty or fifty trebuchets directly outside Zhang Yi's camp, and every day he wanted to throw stones at Zhang Yi's camp. And they sent heavy troops to guard the stones, and these trebuchets were destroyed.

Zhang Yi's camp was so small that he barely supported ten trebuchets. And because the range is much shorter than Cao Cao's trebuchet, it can only be passively beaten. Moreover, the camp is located near the water's edge, in a low-lying area, and there is no way to fight back.

On the first day of the attack, Zhang Yi decisively transported most of the soldiers by ship. Only a few hundred people are left to stare here, mainly Cao Cao does not attack the camp, they stay in the camp, pay attention to the stones in the sky, if it is not unlucky, basically no one will die, because the wall is very strong, see the stones flying over, as long as you jump off the wall to dodge, it is absolutely safe.

The trebuchet is definitely a deterrent when there are many people, but if there are few people, the effect is definitely reduced.

When I watched "The Lord of the Rings", those half-orc phalanxes, a big stone went down, and they smashed into one piece, and they died! But if there's only one person there, you can't kill him with a hundred stones, and then the protagonist will have to be replaced.

Zhang Yi only left a few hundred people for this reason, his camp is definitely not small, and if he leaves too little, it will definitely be seen by Cao Cao. But if you have to leave too much, someone will definitely be hit by a stone, and then it will be in vain.

The mission left behind is still very dangerous. However, Rich and Noble was in danger, and Lu Meng saw that this was an opportunity, so he applied to stay.

Zhang Yi told Lu Meng his purpose, he just wanted to keep Cao Cao as much as possible, not to let him have time to attack the Yuan family, as long as he could delay it for a few months, it was basically impossible for Cao Cao to use troops this year.

Cao Cao's army was in Wei County, and the consumption of food and clothing was huge every day. Moreover, the surroundings of Wei County were basically looted by Zhang Yi, and these expenses needed to be transported from hundreds of miles away, the supply line was too long, and there was a lot of consumption on the road.

And Zhang Yi used fewer soldiers and horses than Cao Cao, and it was a waterway, and the transportation cost was very low, the same grain of one hundred stones, Cao Cao could have fifty stones to transport, and Zhang Yi could keep at least ninety stones.

That's the gap! It is also Zhang Yi's confidence, and he consumes time to kill Cao Cao. If it weren't for Cao Cao's establishment of too many trebuchets at once, Zhang Yi would not have retreated at all, and he didn't want the soldiers he had trained with great difficulty to explain that it would be too cost-effective to explain here.

Zhang Yi re-appointed Buqi as the Taishou of Guangling, guarded Huaiyin with Tang He, led 5,000 men and horses, and guarded Huaipu with Lü Meng, led 3,000 people, and set up a water village in Huaipu for Li Jun's water army to be stationed. Jiang Qin guarded Huailing and led 3,000 people, and Zhou Tai guarded Xuyi and led the water army. Transferred Luo Guanzhong and Wang Xuanmo, Guangling Chang and salt blasphemy orders.

The defense and government affairs of Gwangneung County are basically the same. Zhang Yi appointed and dismissed Zhuge Jin as the Taishou of Lujiang County, transferred Li Jing and Di Qing to Yuzhang, settled in Chaisang, and gathered troops in Chaisang, and sent people to infiltrate Jingzhou.

Cao Cao soon discovered that Zhang Yi had withdrawn his troops, and immediately asked people to rush to the camp, only to find that it was empty. Cao Cao asked the water village to be revoked, and moved the people of Wei County to the Xiapi area.

The whole city of Xiapi was emptied by Zhang Yi at the beginning, but only the family of the king of Xiapi remained, and Cao Cao finally had to get the king of Xiapi to Xuchang.

For these kings surnamed Liu, Cao Cao can't beat or scold, and he still raises them, which is the price of Fengtianzi. If you don't treat these Liu surnamed Wang a little badly, someone will jump out and accuse them. So Zhang Yi kept throwing the pot to Cao Cao, and Cao Cao had to carry these pots if he didn't carry them.

After Zhang Yi was repulsed, Cao Cao also began to make arrangements in the north. A lot of food and supplies were consumed in Xuzhou, and Cao Cao was temporarily unable to attack Jizhou, so he was ready to wait until after the autumn harvest before acting.

However, before attacking, he has to make some trouble for Yecheng. In the end, in desperation, he could only talk to Yuan Tan, hoping that he would lead his troops to Qingzhou and take Guo Tu away at the same time, so as not to let Yecheng fall apart.

Yuan Tan thought about it and felt good. After he arrived in Qingzhou, he was even closer to Zhang Yi's Huainan, and he could trade with Zhang Yi nearby. Bohai County is his sphere of influence, and he can easily get horses, and the place where the horses are traded is in Qingzhou, which is much closer than Yangxin. Moreover, maybe you can also reach an alliance with Zhang Yi and find a foreign aid to come out.

Yuan Tan's idea coincided with Zhang Yi's, and he directly built a seaport (now Qingdao's location) in Buqi County, Donglai, where he made deals with Yuan Tan.

As for Yang Xin, he also has reservations, after all, he still wants to get some benefits from Yuan Tan! Zhang Yi even asked Master Shang to lead his troops to Yangxin, and then drove horses from Yangxin to Buqi, and then transported them to Yandu by sea boat.

It is very convenient to go from it to the salt, and it will only take a few hours if the wind is downwind, and it will not take a day to go against the wind.

Zhang Yi not only collected horses, but also slaves. There is never a shortage of struggles in the steppe, and the Hu people become slaves everywhere. Zhang Yi wants those slaves who can fight on horseback, and they only need two or three ring-headed knives to buy one, which is very cheap!