The infantry brought by Cao Cao this time was mainly Zhang He's local soldiers in Jizhou. He knew very well how strong these troops were when fighting against the cavalry.

Hebei spearmen are famous all over the world. They hold long spears and halberds in both hands to charge, which is very effective in restraining heavy cavalry. Anyway, no matter what heavy armor, they cannot be prevented from stabbing fiercely when they encounter spears and iron halberds. Even if the iron armor cannot be penetrated, people will be stabbed off the horse by huge force.

This configuration is just not resistant to rushing and flying arrows. It is most afraid of being kites because holding a spear in both hands cannot match a shield.

But as long as the command is done properly, use our cavalry to entangle Zhang Fei's heavy cavalry, and the dense formation of spears on our side to output it. Then Zhang Fei's light cavalry will be handed over to the light cavalry of Cao's army to deal with. With four or five times the advantage of military strength, it is still easy to crush.

The key is to make good use of military constraints and use their strengths to attack the enemy's weaknesses when deploying troops. Cao Cao felt that his commander's talent was obviously crushing Zhang Fei.

It’s true that after the bloody battle lasted for a stick of incense, Zhang Fei’s advantage was no longer obvious at the beginning, and the cavalry gradually became entangled.

Even the iron-breasted cavalry could not come out due to conflict. Although they fought to death and stabbed several times the enemy, they were still trapped in the forest of guns and spears and were stabbed and assassinated. Every time Cao's army killed a team of iron-breasted cavalry, they couldn't help but go up to remove the precious whole piece of forged steel-breasted cavalry from the body.

Judging from the exchange ratio, Zhang Fei can still ensure that he kills more than three times the casualties of the armored cavalry for every time Zhang Fei pays, but the number of others is too small and he will fight for nothing sooner or later, so he ordered the entire army to break through in the direction of his origin.

Considering that Zhang Fei only paid a lot of casualties in the final stage of the situation turning, he still took advantage of it most of the time before, and it was still acceptable after a split.

His speed advantage is still obvious. If a pure cavalry wants to retreat, the infantry and cavalry on Cao Cao's side will certainly not be retained.

If Le Jin and Zhang He were allowed to lead the cavalry alone, they would be defeated by Zhang Fei if they were to distance themselves from the main force of the infantry.

Both sides had their own concerns and were afraid of being attacked, so they chased and retreated in a storm. Zhang Fei occasionally turned around and knocked, and then left, and even safely withdrew all more than 10,000 cavalrymen.

The fierce bloody battle lasted for less than half an hour from beginning to end, and the rest were all chasing in mobile warfare. However, in that short battle, Zhang Fei suffered one or two thousand casualties, while Cao's army was close to five thousand. Considering the gap in troops, Zhang Fei could only be considered a loss.

The two sides chased each other until afternoon, and traveled dozens of miles, and had approached the Yijinglou Fortress.

This place was attacked from Yishui to the north. If you want to lead to Jixian and other core hinterlands of Youzhou, you will definitely not be able to get around it. Otherwise, Gongsun Zan would not choose to build a fortress here. (But Gongsun Zan was not strong enough and all the rear was rebelled, so Yuan Shao was not afraid of being stuck in the Yishui channel when advancing. Yuan Shao could get supplies directly from Gongsun Zan's rear, and Gongsun Zan only had an lonely city fortress left)

...

There are still thousands of Yuan Xijun defending the ruins of Yijinglou. The earth platform is ten feet high, and there are several feet tall buildings built with hard stones and huge trees on the platform. Zhang Fei has never been interested in attacking for a strong attack, but he just divided his troops to siege him to death.

But this siege has lasted for some time, and the attacking side will strengthen the encirclement, so now it is the "Lou Outer Ball Camp". The camp in the siege of the Lou Fang has become an iron barrel circle like a city, and it will never allow the people inside to break out. When Ji County is broken, Yuan Xi himself will die, and this kind of place can be directly surrendered.

The fortifications of the offensive and defensive sides were only 150 steps apart, and they were not even worried that the defenders would use bed crossbows or catapults to bombard the camps in the building, because Zhang Fei knew that there were not so many supplies in the building, and the fortifications that could be lost long ago. The fortifications of the two sides were close, and the radius of the surround circle of the attacking party was short and the construction volume was small.

At this moment, Zhang Fei and Xu Huang retreated to the besieged camp and immediately entered the camp by several gates. There were 30,000 infantry troops in the camp, which could completely block Cao's pursuit.

A few cavalrymen in Cao's army were not good at heart and did not react for a while. They chased Zhang Fei and rushed to the camp in a daze. As a result, they were all shot into hedgehogs. After dozens of them died, the warning effect was achieved. They naturally calmed down and no longer died in vain.

Cao Cao either went around without fighting, and went straight to the enemy's back to rescue Jixian. If he wanted to remove Zhang Fei's nail, he had to first break through the camp where Zhang Fei surrounded the building.

Yi Jinglou was built by Gongsun Zan on the north bank of Yishui, and the south side could overlook the blockade of Yishui waterway. If Cao Cao walked around, it meant that the waterway was cut off and the benefits of the navy were abandoned, so this was definitely unwilling to bear.

Cao Cao then took the pursuers around Zhang Fei's camp, and firstly he found out the general scale of Zhang Fei and saw how strong the camp's fortifications were.

The defense effect of the camp was obviously not comparable to that of the surrounded fortress. Cao Cao estimated that he spent three or five days to destroy the geographical advantages and disadvantages of both sides. The subsequent battle with Zhang Fei outside the city was equivalent to fighting a field battle with Zhang Fei.

The most likely position to be broken through in Zhang Fei's camp is the north side. Because the south side is close to Yishui, Cao Cao had to fight a landing battle directly before attacking the camp, which was too much punishment.

If you go deep into the north bank of Yishui and fight back with great difficulty, there will be no punishment for logging in.

At the same time, the remnants of Yuan Xi's army in Yijing Building may also help with some support when fighting with the wind. Generally speaking, there is a great hope to defeat Zhang Fei.

But what really worried Cao Cao was that he thought that Zhang Fei would not have had another conspiracy when he responded like this, right? Zhang Fei relied on the camp here and hoped to solve the problem?

At the moment, there was no sign of the enemy's intentions, so Cao Cao had to make careful verification. While ordering the preparatory measures for the attack, he spread the cavalry scouts out wildly. The radius of reconnaissance was even widened to unprecedentedly thick. Once abnormal movements were found, he could adapt to the situation immediately.

Zhang Fei shouted and fought in Weilou Camp every day, scolded Cao's army, and fought against some heavy equipment. He fought for two days, and dragged it until July 19th.

Just as Cao Jun felt that he had prepared a considerable number of attacking equipment and the soldiers were also regaining their energy and recovering their state. In the evening of that day, a bad news suddenly came from the rear.

A team of urgent scouts from Quanzhou County, Yishui River mouth rushed into Cao Cao's camp. Cao Cao was having supper at that time.

"Prime Minister! Yesterday, a large number of Liu Bei's warships were suddenly found outside Quanzhou Port (Tianjin). Our navy failed to fight in a hurry. Now the enemy has seized the Hekou Water Village. It has also burned the affiliated water villages that are on guard. The enemy has blocked the sea entrances of Yishui and other rivers!"

Cao Cao suddenly felt his mind buzzing and almost got into trouble.

This blocked his fleet's retreat route? It could not enter the sea in the inland river Yishui? It could not slide south along the Bohai Sea coast and into the Zhangshui River or the Yellow River?

"This is impossible! Our army has set up water camp outposts along the coast of Yuyang. How can we not be warned in advance?" After a brief dizziness, Cao Cao finally caught a clue and immediately threw a bowl and scolded him angrily, spreading all the wheat rice on the table.

The messenger was helpless and cried: "Prime Minister, the enemy is very familiar with the hydrology and the geography of the nearby seas, and did not sail along the coast.

Instead, we went straight to the Quanzhou Port Water Village from the far sea in Liaodong to the west. When we appeared at the end of the sea view, we were less than twenty miles away from the Quanzhou Water Village! Therefore, our army's warning water village in Yuyang could not be warned in advance!"

Cao Cao was stunned when he heard this. After a long reaction, he remembered a question. He turned around and asked Cheng Yu: "Why did our navy not master such a method of navigation?

A few years ago, when Lu Xun and Naruzi helped our army train naval commanders, if they didn't stick to the coast, they wanted to go directly to Sanhan from Donglai. Even if they rely on Sinan to watch the sun and the moon, they would still have more than a hundred miles of error when they arrived!

Why are ships from Liaodong so accurate in finding errors between north and south? Can they avoid outposts along Yuyang and other places to guard the water villages? Could it be that Liu Bei is really helpful?"

The more Cao Cao said, the more discouraged he became. The last half of the sentence was to suppress his unwillingness and try to lower his voice to question, which was almost like a murmuring to himself. Cheng Yu also knew that the Prime Minister was afraid of damaging his military morale.

Destroy teeth and swallow them!

At the same time, a trace of fear gradually arose in Cheng Yu's heart.

He inexplicably remembered the bold words of Cao Cao whipped the Yishui morning before yesterday, saying, "People say that Li Boya shines thousands of miles, Zhuge Liang's magical plan is so good that I can't stand it!"

That’s not the case! The other party can clearly achieve these things that you think are impossible! It’s just using tricks you can’t imagine!

But, it's all really coming!

In fact, the ability of Zhao Yun and Taishici's navy to sail against the shore and to find the right direction accurately and directly plunge from the deep and distant seas to Quanzhou Port Water Village is obviously using a navigation technology called "latitude navigation method".

In history, the Arabs mastered this thing well during the Tang and Song dynasties and used it to efficiently shuttle through the Indian Ocean.

The Chinese at the end of the Han Dynasty could not say that they did not understand this thing at all. After all, the voyeurs could still see the angle of the sun and the stars. But after all, there was no sextant theodolite, and the calculation of trigonometric functions was not quantitatively accurate enough, so they only estimated the number and would not be very accurate.

With Lu Xun's talent, he helped Cao Cao edit and practice sea navigation sand boats for more than four years. He falsely reported his age at the age of thirteen, and he still often drove a thousand miles away. The latitude error can be 100 miles, and the error rate is close to ten%.

When crossing the ocean, you often have to see the land again and immediately go to the dock to ask where it is, remark it on the chart, and then drive to the real destination for a while to retrieve the error.

The navy on Liu Bei's army, on the one hand, popularized more mathematical tools of Li Su and Zhuge Liang, and could accurately analyze quantities. On the other hand, the naval chart surveying is more accurate, accurately marking the latitude of each point along the Bohai Sea coast, and the latitude of star-watching and sun-watching is also measured by an order of magnitude more accurately than Lu Xun.

Of course, these two points cannot be solved by theoretical study alone. If you have knowledge reserves and practice, the troops under Zhao Yun and Taishi Ci actually sailed back and forth for more than 13,000 miles last year, and at the farthest they reached the Gulf of Siam.

The experience of navigation is already extremely rich. It can be said that there is no second navy in East Asian world that has experienced such a long voyage. Therefore, the above theoretical knowledge can be fully mastered and used as long as you want.

Otherwise, even if you tell Lu Xun the mathematical tools that Li Su, Zhuge Liang were told to Lu Xun in its entirety, and let Lu Xun copy the answers, it might not be accurate. Just like in a physical and chemistry laboratory, you tell the poor students about the experimental steps, and the poor students may not be able to do the experiment.

In any case, Zhao Yun and Taishi Ci had already used a sneak attack that Cao Cao had never thought of, cutting off Cao Cao's retreat.

From taking over the enemy at sea, to secretly heading north at the beginning, to lurking and enduring in Liaodong for several months, I never exposed myself before I encountered Cao's army attacking Liaodong. Every step requires great strength.

Cao Cao didn't see through it, because he was indeed misled because his lack of intelligence was misled, and his technical imagination was also somewhat lacking.

It is not a sin of wisdom.

Cao Cao and Cheng Yu are certainly unable to understand the above reasons at this moment. Perhaps they will have to wait until the war is over before the answer will be solved.

But no matter what, the most important thing now is to deal with it by chance. Even if you can't figure out why Zhao Yun appeared, you still have to concentrate on dealing with this mutation.

What should I do now? Should I continue to prepare to attack Zhang Fei, or turn back to deal with Zhao Yun? Or should I decisively give up all the navy and supplies, abandon the ship and walk through the siege?
Chapter completed!