Guo Jia said goodbye and left.

Since Lu Bu was calculated that there should be no food or food, Cao Cao would look at Lu Bu's army stationed on the opposite hill in the military camp every day.

The battle flag was still dancing in the wind on the hills, and Lu Bu still seemed to be in a dilemma of shortage of food.

Looking at the hill full of battle flags, Cao Cao's face looked very ugly.

The Cao family scouts had a lot of experience, and it was impossible for them to judge how much food and grass the enemy had.

But Lu Bu couldn't finish his food no matter how much he ate it.

No matter how he thought about it, Cao Cao couldn't figure out what method he used to make it impossible to eat food and grass.

When Guo Jia came to his side when he was worried and didn't know how to find out how much food Lu Bu still had.

"Lord, the scouts I sent to investigate the situation have returned." Guo Jia said: "They brought back the news that they did not find any secret passages transporting food and grass near the hill.

"There is no secret passage?" Cao Cao asked in surprise.

"No." Guo Jia's answer was exactly what Cao Cao wanted to hear the least.

"Have you asked the scout to check it a few more times?" Still not giving up, Cao Cao asked him.

"The scouts I sent out are all experienced. They searched four or five times without finding a secret passage, but they still found nothing." Guo Jia said: "Actually, lord doesn't have to pay too much attention to this matter. I always feel that although Lu Bu did not dig secret passages by the mountain, he must have other ways to transport the food and grass to the mountain."

"What can I do?" Cao Cao asked, "Can they dig out a secret passage underground?"

Speaking of this, Cao Cao's eyes lit up.

Seeing what he was thinking, Guo Jia quickly asked: "Does the lord think that Lu Bu will hollow out the mountain and lead to Xuzhou to transport food and grass to the mountain?"

His question confused Cao Cao: "Why do you have to keep going to Xuzhou?"

"Have you heard that the lord is transporting food and grass from Xuzhou?" Guo Jia asked again.

Cao Cao immediately didn't know what to say.

The scouts he sent recently were all searching for Lu Bu's food and supplies.

However, no matter how the scouts searched, they could not find out how the food and grass were sent to the mountain where he was stationed.

"You mean..." Cao Cao asked in confusion: "It is impossible for him to hollow out the mountain?"

"Does the lord think he can do it?" Guo Jia did not answer, but asked back.

The project was very large when the mountain was hollowed out.

Xuzhou did not convey even a piece of food. If Lu Bu really opened a path underground, the distance would take two or three years to complete it without a year.

It took so long that even if the tunnel was dug, he would not be able to hide his eyes and make everyone unaware of it.

"Fengxiao means that there is no way to have a passage dug out underground?" Guo Jia said clearly, but Cao Cao asked with a very ugly face.

"I don't want to say that either, but in fact I think that's the case." Guo Jia replied.

"You can't just waste it like this?" Cao Cao asked Guo Jia: "Don't Fengxiao think what we should do to achieve?"

"Of course we have to do it." Guo Jia said: "I think it's time for the lord to attack Shangang."

"They are above, we are below." Cao Cao shook his head: "If we force an attack, we don't know how many soldiers will die."

"Although we can't find any trace, I believe Lu Bu must have a solution to the military rations." Guo Jia asked Cao Cao: "Don't the lord want to know why he brought so little baggage so that the soldiers can still fill their stomachs?"

Cao Cao really wanted to know how Lu Bu did not leave any traces, but also allowed the soldiers to be short of military rations until now.

He frowned and asked Guo Jia: "How do you think we should attack the mountain?"

"Have you noticed that the four sides of the mountain are not very steep?" Guo Jia pointed to the hill where Lu Bu was stationed and said to Cao Cao: "No matter where our army launches an attack, once they can't support it, they will escape from the other side."

"What are you going to do?" Cao Cao asked him.

"Dig deep trenches in front of the mountain to bring nearby water sources here." Guo Jia said: "Build them a mountain protection river, leaving only one exit to evacuate. With river isolation, we can also set fire at the foot of the mountain. Because we are separated by the river, we can set fire at the foot of the mountain. At that time, the lord will lead the army to fight on the mountain? As long as the fire is together, I don't believe that Lu Bu will not go down the mountain."

The strategy proposed by Guo Jia is really the most suitable method to attack Lu Bu at the moment.

Cao Cao immediately ordered Xu Chu next to him: "Zhongkang, send our military orders to let the soldiers open a river around the hills. The flow depth can be at least four people, and the width must be a distance that the war horses leapt in the air, which is impossible to jump. When the excavation is completed, the water from the nearby river will be lured there. I want to see what other ways Lu Fengxian can do to deal with these."

******************************************************

Guo Jia suggested to Cao Cao that he would dig a river around the hills.

Cao's army immediately took action.

Countless Cao's soldiers gathered at the foot of the mountain, sweating profusely and digging the river.

On the hillside, Lu Bu and the generals looked at Cao's army at the foot of the mountain.

Zhuge Jin came over: "Marty Chu, Cao Cao seemed to be trying to drive the river around the hills."

"I saw it." Lu Bu nodded: "He wanted to use the river to block us on the mountain first, and then set a fire at the foot of the mountain. With the river to block it, the fire would not spread around and would not affect Cao's army. We don't want to go down the mountain at that time, we have to go down the mountain."

"What should I do?" Sun Ce asked Lu Bu: "Is it possible to wait on the mountain for them to do this?"

"Of course not." Lu Bu smiled slightly: "He does whatever he wants? Do you think this is the former Xia Pi? He thought so, I was no longer Lu Bu in Xia Pi City!"

"Zilong." Lu Bu said to Zhao Yun on the other side: "Cao army digging the river today, and it will definitely be very tired at night. It is a good time to burn their military camp."

"I understand." Zhao Yun agreed, then asked Lu Bu: "Does all the air forces attack, or only part of the attack?"

"Since you want to attack, of course you will attack." Lu Bu said: "Burn them first and let Cao Cao know that not all matters are taken over."

"By the way." After giving the order, he said to Zhao Yun again: "Remember to drop a few more oil bottles on Cao Cao's tent."

"Don't worry, Mr. Chu, I understand." Zhao Yun agreed.

During the day, Cao's army dug a river at the foot of the mountain, but Lu Bu on the mountain did not respond at all.

The river channel does not open in a day or two.

Surrounding the hills, it is impossible to open a river channel in a month or two.

Lu Bu was really not in a hurry to deal with the Cao army at the foot of the mountain.

What's more, at night, when the oil bottle was thrown, I don't know how many Cao's army would die and be in the fire.

And Hebei Africa is eager to compete with Cao Cao during the day?

Lu Bu was not anxious or impatient, and had no intention of dealing with Cao's army. However, Cao Cao was very anxious when he looked at the Cao's soldiers under construction.

It is unclear how many days Lu Bu's army can last for food and grass, so he can only count on the excavation and setting fire to the mountains.

As long as the fire burns, either Lu Bu will be burned to death, or he will have to go down the mountain to face Cao Cao.

Although the number of soldiers brought was not large, only more than 40,000, Cao Cao was very confident in them.

All the 40,000 soldiers were Tiger Guards.

The Tiger Guards are all warriors of war. They have strong discipline and will not show even a trace of chaos whether they advance or retreat.

No matter who you meet such a large army, you will have a nightmare that you may never wake up.

The Cao army soldiers dug all day, but only dug some deep pits at the foot of the mountain.

These pits surround the hills, and as long as they are connected into a line, they are a deep ditche.

Connecting a pit into a ditche is not as simple as digging a pit. It is impossible to do it without ten days or half a month.

The sky gradually darkened.

Guo Jia asked Cao Cao: "Lord, do you have to continue tonight?"

"Of course we have to continue." Cao Cao said: "The two armies of Yuan Benchu ​​should have set out. They are not dealing with Lu Bu. If they were attacked by them first, what's the point of us attacking Xuzhou?"

Cao Cao decided to continue digging the canal at night, and soon another group of Cao troops replaced the one who was sweating profusely during the day.

At the foot of the mountain, Cao's soldiers were shaking torches and digging the canal.

Looking down from the mountain, the torches raised by Cao's army were like the stars at night, brightly illuminating the lights below the mountain.

"Cao Cao really wished he could destroy us immediately." Looking down at the mountain, a smile appeared on the corner of Lu Bu's mouth. He said to everyone beside him: "If he knew that everything he did now would be of no use to us, I don't know what he would think."

"Master Chu, when will the Air Force attack?" Zhao Yun was already a little impatient and asked Lu Bu.

Lu Bu replied: "Wait a little longer before they change people. Those who returned to the military camp have not yet fallen asleep. When they are all asleep, it is not too late for us to do it."

Seeing that the soldiers who were digging the river in Cao's army had changed, Lu Bu still did not intend to launch an attack immediately, Zhao Yun and others were also a little anxious.

Looking at the Cao army who was busy at the foot of the mountain, the two generals Zhao Yun and Sun Ce wanted to rush down immediately and kill them on the spot.

Especially Zhao Yun, he looked at the Cao army camp a little further away from time to time, with a strong desire in his eyes.

Zhao Yun was waiting for Lu Bu to order the Air Force to set off, while Sun Ce could only wait and see on the mountain.

After waiting for nearly an hour, the night became even darker.

Lu Bu looked up at the sky.

The night sky without moon is filled with stars, and the twinkling starlight and the jumping fire light on the ground are like greeting each other.

"Zilong, prepare to set off." After a while, Lu Bu finally said this.

Zhao Yun, who had been impatient, received the order, immediately responded, turned around and called on the soldiers to attack the Cao army camp.

After the order was issued, the Air Force soldiers found their respective aircraft.
To be continued...