The results of the test proved that the tactics mentioned by Liu An to take advantage of the night to sneak up on the city were feasible. Even if the defenders are on guard, if the raider picks some special nodes and uses the climbing rope to sneak attack the city, the chance of a sneak attack will be very high.

Later, when Zang Ba and others asked Liu An how to guard against this kind of sneak attack, Liu An told them a method that sounded very unreliable - outside the main city wall, add a wall that does not need to be too high and does not need to be defended by people.

That's all, this is what Jin Jue said to Ma Dai at that time. After Bao Chu led more than a dozen elites to almost steal the city for the first time, to be honest, Ma Dai at that time was suddenly frightened by Jin Jue's unbelievable way of attacking the city, at that time, he asked how to crack this method of attacking the city at night, but he didn't expect that Jin Jue actually had to answer his question, and gave a method.

Later, Liu An went to Xuzhou, among the six leaders of the Taishan thieves, the Sun brothers and the two of Donglai County took Liu An's words as a joke, first of all, building a city wall outside a city is not a small project, in this troubled world, food is very scarce stage, everyone is busy playing turf, how can anyone build a city wall outside the city for a child's joke?

However, there are people who do it.

The first person is none other than Changba.

In fact, Changba's ambition is not as great as recorded in history, and the reason why he has betrayed Cao Cao many times is that there are many deep-seated reasons that outsiders and future generations cannot understand. And Changba in this time and space, since he has made up his mind to join Liu Bei, and the surrounding area is his brother's territory, there is almost no room for expansion.

Therefore, Changba regarded himself as a nail, in case one day, Yuan Shao really had to defeat Cao Cao, and his brothers could not stop Yuan Tan's attack, then, in the south of Langya County, which was ruled by Changba, the county seat of Kaiyang County became the first line of resistance to Yuan's army.

Therefore, Changba really had to recruit the people to build a city wall about one person higher than the inner city wall around the city outside the county seat of Kaiyang County.

Kaiyang County itself is a small county seat, the population in the city was originally less than 20,000 households, after these years of Taishan thieves management, the surrounding areas are still in turmoil, here has become a relatively peaceful place, the establishment of more than double the surrounding escape from the war of Yanzhou, Qingzhou and Xuzhou people.

Therefore, that time, it was not difficult for Changba to collect people and build the city wall.

The second person is Zang Ba.

Zang Ba now governs Ju County, the county of the original Langya County, and the county of a county is naturally a big county, however, the former Langya County Taishou Xiao Xian is not a capable person, and it is not easy to toss a good Langya County, so although Ju County is not more prosperous than Kaiyang County.

Therefore, it is a bit difficult for Zang Ba to build a wall that bypasses the whole city.

Zang Ba deserves to be a famous general, and he thought of a more clever way.

Judging from the current situation, considering the enemies that Ju County may encounter, Zang Ba knows that in order to show his benevolence, Liu Bei has given up the entire Langya County to them, so the probability of Liu Bei sending troops to attack them will be very small.

On the contrary, before, when Beihai County was conquered and Donglai County was taken, the Taishan thieves undoubtedly greatly reduced the face of Yuan Tan, the son-in-law. If it was just Yuan Tan, to be honest, the Taishan thieves were not afraid of him, and it would not be difficult for Zang Ba to take the opportunity to take Qingzhou south of the Yellow River. I'm afraid that as soon as they drove away Yuan Tan here, Yuan Shao came with an army over there.

It's called beating away the little ones and irritating the old ones.

And Cao Cao has done too many things to go back on his word, and Zang Ba has to guard against them. In particular, he had actually seen that the Sun brothers, especially Sun Guan, were more optimistic about Cao Cao in private, and had long had the idea of taking refuge there.

Therefore, when Zang Ba built the city wall, he only built the west and north walls outside the county seat of Juxian County, and the east and south sides were temporarily shelved.

Changba's move, which made outsiders, even Liu Beijun, seem very redundant, saved his life.

The characteristic of Xiahou Yuan to lead the troops is to be fast! This is true even if he is leading an infantry.

In addition, the Sun brothers deliberately let go of the southern passage of Taishan County, this sneak attack was extremely sudden, even if Kaiyang County had an additional city wall that made Xiahou Yuan feel great, and the county seat of Kaiyang County, which was the leader of Changba, was almost blown down by Xiahou Yuan's army.

However, it was really this inconspicuous city wall that made the Changba army breathe a sigh of relief and persevered. And when the morale of the Cao army under Xiahou Yuan was about to stop the attack, the generals and soldiers were stunned to find that it was almost impossible for the Cao army in the outer city wall to withdraw again.

Changba seized this opportunity, and a rain of arrows and rolling wood and stones came down, and the Cao army in the outer city wall suffered countless casualties at once.

After the war, Xiahou Yuan had counted, and in this battle, the siege soldiers actually lost ninety percent.

This time, Xiahou Yuan's troops of 15,000 people attacked Kaiyang City, but he didn't expect to lose one-fifth of it in the first battle.

Fortunately, in the panic, Changba only had the energy and time to concentrate on the strongest side of the Cao army's siege, otherwise, the Cao army's losses in this battle would be greater.

After the Battle of Kaiyang City, neither side had enough strength to wage war against the other.

Xiahou Yuan's Cao army suffered serious losses, and the losses of the Changba army in Kaiyang City were not small, after all, Xiahou Yuan still took a lot of advantage at the beginning of the sneak attack, and used the sneak attack to kill many soldiers defending the city.

Next, Xiahou Yuan had two choices.

The first choice, taking advantage of the heavy losses of the Changba army and the inability to fight back, he immediately led his troops to bypass Kaiyang City and go straight to Donghai County. At this time, the defenders of Donghai County definitely did not expect that Cao's army would launch an attack from the north of Donghai County.

The second option, Xiahou Yuan used the remaining forces to trap Kaiyang City and attract the defenders of Donghai County to come for reinforcements, and at the same time, he reported his specific battle report here to Cao Cao, so that Cao Jun could make timely adjustments, or, continue to increase troops to Xiahou Yuan, and keep an eye on the northern part of Donghai County; Or, like in the Second Battle of Xuzhou, after attacking Pengchengguo, divide your troops to attack Donghai County from the eastern border of Pengchengguo.

It only took a quarter of an hour for Xiahou Yuan to make a decision - immediately abandon Kaiyang City and go straight to Donghai County.

However, what Xiahou Yuan didn't know was that as early as when the Sun brothers took the initiative to make way for Cao Jun, the spies that Liu Beijun had planted here had already found out about Cao Jun's movements.

(End of chapter)