"Sima, there is indeed an abnormality in the underground of this section of the city wall!"

An old craftsman nervously reported to Cao Yuan, who was left in the open space under the city, and after listening to it, Cao Yuan nodded, but he was not as anxious as when he thought that Bai Bojun might dig a tunnel.

If you find the tunnel dug by the Bai Bo Army, everything will be easy!

"But are there any other places where you have found any changes?"

Not long ago, Cao Yuan had ordered a row of large water tanks to be buried under this city wall in turn, and each large water tank was assigned soldiers and craftsmen to spy on the situation under the ground.

Now the fear is not that the White Wave Army is digging tunnels, but that the White Wave Army has dug several tunnels at the same time, and the defenders in the city will not be able to find out in time.

"At present, only one has been found, and it is estimated that it is used by thieves outside the city to pass through the city wall and attack the city gate at night."

The old craftsman replied cautiously.

Cao Yuan heard the old craftsman's answer that there was only one authentic passage, and raised his thick eyebrows, but he didn't have too many doubts.

Siege and digging tunnels is not only a technical job, but also a time-consuming and labor-intensive hard work, and the more you dig to the back, the more manpower will be used.

If you are not careful, let the water of the moat penetrate into the tunnel, or directly dig up the ground, this tunnel will be exposed in advance, and it will not have the effect of transporting troops and assault, so it will naturally only be able to give up halfway.

Outside the city, the Baibo army besieged the city for only half a month, and it was estimated that the time to start construction could only allow them to have a tunnel to dig to the edge of the city wall.

"Where did you dig it all up?"

"Estimating the sound, the tunnel outside the city is also within ten zhang of the bottom of the city wall, and if you give the thieves outside the city a day, you will be able to dig the tunnel into the city!"

"Hmm."

These are similar to Cao Yuan's estimates. Cao Yuan thought for a moment and asked again:

"Then if you gather all the manpower and material resources in the city, can you dig a tunnel before the tunnel of the thief army outside the city is dug under the city wall, and cut off the tunnel of the thief army outside the city!"

"If there is enough manpower, and then rush to work overnight, it is still very likely that the ground will be broken from inside the city and then the tunnels outside the city will be dug up."

"That's good, I'll send you another 500 prisoners, 300 militiamen, and 100 soldiers, and you will personally survey the tunnels and mobilize people to dig up the tunnels outside the city for me. And then—"

The old craftsman saw Cao Yuan's groaning appearance, knew that he still had a follow-up decision, and bowed down and waited for Cao Yuan to speak.

"I'm going to use smoke to attack, is it possible to carry it out?"

To deal with the tunnel, there are various methods such as earth attack, water attack, smoke attack, etc., although Cao Yuan can come up with the method of attack, to the specific implementation of the actual situation, it is necessary to put forward the practical opinions of the craftsmen.

The old craftsman lowered his head and pondered for a while, and then slowly said to Cao Yuan:

"The smoke attack plan is indeed feasible, but-"

"Just what?"

"The villain doesn't dare to hide Sima, it's not difficult to break the tunnel transportation plan of the thief army outside the city, but according to the villain, it is extremely difficult to resist the tunnel siege plan of the thief soldiers outside the city!"

"Oh, what does that mean?"

"There are few soldiers in the city, although you can dig a long trench to cut off the tunnels outside the city to enter the city, but if the thieves outside the city fail to make this plan, they are no longer determined to transport troops into the city, but at the expense of manpower and time, they will break the ground together, and attack the city in a hundred ways, Linfen City has been in disrepair for a long time, and it has only recently been repaired, and the city foundation is only afraid that it will not be able to resist the excavation of the thieves outside the city!"

The old craftsman's concerns are not superfluous, digging tunnels to transport troops, but also need to ensure the safety of their own soldiers, reduce the movement of the ground, and prevent being discovered by the guards guarding the city, but if the Baibo army blindly destroys the city foundation, then this newly repaired Linfen City, which has only recently been repaired and has many omissions, is indeed difficult to resist.

However, this is already a later matter, at present, we must first gather the manpower in the city and destroy the first tunnel of the White Polish Army outside the city, so that we can spare our energy, and then find a way to deal with the follow-up offensive of the White Polish Army outside the city.

Cao Yuan silently gathered this big problem in front of the Linfen city defense in the future, and then ordered the deployment of manpower in the city, began to break ground and dig tunnels, and started construction overnight, with one night, it was necessary to dig outside the city, cut off the tunnels of the Baibo army outside the city, and use the smoke attack strategy to destroy the tunnel transportation plan of the Baibo army.

That night, the soldiers and civilian servants in the city stepped up digging tunnels, while surveying and correcting, and continued to approach the Baibo Army tunnels outside the city, and in the early morning of the next day, the soldiers and civilians in the city finally dug near the tunnels outside the city.

The soldiers and people who were digging the tunnel also stopped the tools in their hands and waited for the Bai Bo army to enter the tunnel again.

After the Baibo army entered the tunnel, the soldiers and civilians digging the tunnel also carefully slowed down their movements, and when they were close to the breach, there was already a large amount of half-dry and half-wet firewood and grass in the city, which was rushed into the tunnel. Subsequently, several skilled craftsmen waved their short hoes and broke through the tunnels of the Baibo army outside the city.

Immediately afterwards, the other personnel began to evacuate, a large number of half-dry and half-wet firewood and grass were also stuffed in the gap, one by one, giving birth to a large amount of smoke, and the craftsman with wet linen towels wrapped in his mouth and nose made sure that the task was successfully completed, and then finally retreated along the tunnel, and then everyone started to fill the entrance of this section of the tunnel with earth and stone, and sealed this entrance.

The people outside the tunnel were happy to complete the task, but the tunnel became a ghost, and the Bai Bo soldiers, who found that the tunnel was horizontally cut and dug through, did not have time to exit the tunnel, and a large amount of smoke had already filled the entire tunnel.

Working in the tunnels, the oxygen needed by the white soldiers is highly insufficient, and after working for a period of time, they need to exit the tunnels to rest. And right now, there is a lot of smoke in the tunnel, and if you want to live, Bai Boshi has to quickly exit the tunnel, but the more you run, the more oxygen your body consumes, and the more smoke you inhale when you breathe through your mouth and nose.

Except for those Bai Bo soldiers who had just entered the tunnel, all the Bai Bo soldiers who had already penetrated into the tunnel were not spared, and they all ran and pushed, inhaled a large amount of toxic smoke, and finally fell into the tunnel······

Guo Tai outside the city originally planned to drive the army to attack for half a day today, attracting the attention of the city defenders, so that his own tunnels could successfully dig through the city walls and enter the city.

Then wait until the night, when the defenders who had defended the city all day were exhausted and fell asleep, they selected elite soldiers from outside the city through the tunnels, secretly entered the city, and combined with the inside and outside, and captured Linfen City in one fell swoop.

But now, a large number of their own soldiers and craftsmen who excavated the tunnels have died, and if they want to continue digging the tunnels, it will be impossible to carry out in a short period of time.

Therefore, although the Baibo army on that day had obviously left the camp and was ready to attack Linfen City again, after being arrayed for a long time, it did not attack the city for a long time, but retreated back one after another.

Standing at the head of the city, quietly watching the Baibo army outside the city withdraw to the camp one after another, Cao Yuan did not feel happy or happy like the soldiers around him.

"The Lord can't raise a division out of anger, and he can't be angry and cause war", Guo Tai's tunnel transportation plan was his own way to govern his own people's body, cut off and destroy, and killed a lot of soldiers, Cao Yuan can be sure that Guo Tai must have jumped like thunder at this time, but when he was angry, he did not force the attack because of anger, but after slowly seeing the situation of the offensive and defensive sides, he decisively gave up the forced attack and chose to retreat rationally.

Such an enemy is the real tricky one, this Guo Tai, who can crisscross Hedong and Taiyuan several places, under the encirclement and suppression of officers and soldiers, continues to grow bigger, and even grows to the point of attacking the city and defeating the county soldiers in turn, it can be seen that he is also a reckless hero, and it cannot be regarded as an ordinary grass bandit.

After estimating the combat strength of the Baibo army before, Cao Yuan agreed with Yan Xing that he would defend Linfen City for half a month, dampen the sharpness of the Baibo soldiers who came from the counterattack, and then join forces with Yan Xing's army to attack together and defeat the Baibo army.

And now it seems that even if the Baibo army does not care about casualties and sends soldiers to dig the city foundation, as long as Cao Yuan defends properly, continues to hold on to Linfen City, and frustrates the morale of Baibo's soldiers, with the food and troops in the city, he can fight with the Baibo army outside the city for more than half a month.

However, Cao Yuan did not believe that Mrs. Guo would not be able to see the plans of their side, if the Bai Bo army decisively withdrew from Linfen City as they did today, and no longer gathered a large number of troops to confront the soldiers and horses of Yan Xing's side, but adopted the previous guerrilla mobile warfare method, then his own side, in turn, would become passive, and if he wanted to completely destroy the Bai Bo army, he would have to engage in tug-of-war and attrition with the superior Bai Bo army.

This point is not only what Yan Xing, who intends to hold Linfen City and eliminate the main force of Baibo, does not want to see, but also Cao Yuan, one of the people of Hedong, does not want to see, his hometown Pingyang is still under the control of the Baibo army, once the war is protracted, according to the situation that Hedong County is now threatened by the north and south, I am afraid that Yan Xing's side may not be able to drag over the Baibo army that can flow through the four fields.

So, is it appropriate for him to convey the signal of attack to Yan Xing on the other side of Fenshui at this time?

Cao Yuan fell into hesitation, this decision was even more difficult than defending the city wall.

At present, although the morale of the Baibo army outside the city has been frustrated, but the main force has not been damaged, it is still a great risk to launch an attack at this time, but if it is not signaled and delayed, once Guo Tai withdraws the main force of the Baibo army, it will be even more difficult to fight in the future.

After thinking about it for a long time, Cao Yuan finally made up her mind.

"Light the wolf smoke!"

After Cao Kite's order was issued, three wolf smoke rose together on the head of the city of Linfen, soaring into the sky, looking at it from a distance, just like three black pillars of optimism, it was spectacular!

And the Bai Bo soldiers outside the city also saw the wolf smoke rising on the city, which is a very incredible thing for them, in the past, when the Bai Bo soldiers attacked the city fiercely, they had never seen it, the city guards on the city head, lit the wolf smoke in an emergency, but now, they did not launch an attack on the city, but the other party defending the city hurriedly lit the wolf smoke, and one point, it is three.

Bai Bo soldiers soon saw this scene on the head of the city, reported to Guo Tai in the big tent of Qu Shuai, Guo Tai, who had just suppressed his anger, was stunned for a moment after getting this information, and quickly reacted, with Han Xian, Hu Cai, Yang Feng and other large and small Qu Shuai, together quickly rushed out of the big tent, came to the open space of the military camp, and looked at Linfen City from afar, sure enough, on the head of the city, there were really three wolf smoke rising to the sky, straight and thick, straight into the sky.

"It's really strange, in the past, we waited for the offensive to be like a tide, but the defenders on the city could not move, today we are waiting for the offensive, but on the head of the city, there is an urgent wolf smoke, tsk!"

Hu Cai looked at the three wolf smoke on the head of the city, and was amazed, Han Xian and Yang Feng looked at each other, and they couldn't understand the thoughts of the defenders at the head of the city, while Guo Tai stared at the three wolf smoke on the head of the city, and after a long time, he suddenly burst out into a burst of laughter, laughing so that Han Xian, Hu Cai, Yang Feng and others around him were inexplicable.

"Okay, this Xiliang army in Linfen City, fortunately defeated us and other battles, and it was so bold, not only was it not afraid that we would continue to attack the city, but it was worried that we would withdraw and flee!"

"What does the handsome mean—"

Hu Cai looked at Mrs. Guo in disbelief and asked.

Mrs. Guo sneered, pointed to the three wolf smoke on the head of the city and said:

"This guy, where is the wolf smoke in an emergency, this is the signal of the Xiliang Army on the east bank of Fenshui to attack our army together!"

"Huh?"

Hu Cai and the others were all stunned, although the Xiliang army was elite, but they heard that their capital Luoyang had been captured by the Dongdong coalition army of Kwantung Prefecture, and they were too busy to take care of themselves in the rear, how many soldiers and horses could be on the front line, and no more than 20,000 people died, and their Baibo army claimed to have more than 100,000 people, of which there were 50,000 or 60,000 strong people, and now most of the strong ones are gathered under this Linfen City.

The defenders of the city took advantage of the fortified city, and if they did not fight, they would barely be able to support some more time, but if they fought a decisive battle in the wilderness, how could they compete with the outnumbered White Polish army with their small strength.

The White Wave Army had fought a few battles with Niu Fu's Xiliang Army before, and although these Western Liang Troops were much stronger than Niu Fu's Western Liang Army defending the city, if it came to field battles, the White Wave Army really didn't believe that these Western Liang Army could be more powerful than the Xiliang Iron Cavalry led by Niu Fu himself, and they could defeat the main force of the White Wave Army with fewer enemies and more enemies.

Mrs. Guo's thoughts were similar to those of Hu Cai, Yang Feng and others, and he said with a smile:

"Immediately send more scouts in the army, along the river to sentry into the movement of the enemy on the opposite bank, although the other side has the advantage of boats, you can choose the river bank, a large number of people to cross the river, but our army is far more than the other side, as long as the other party's movement is discovered in time, I will come with a large army, push and push their soldiers and horses down the river!"

"Haha, drive all the landlubbers of the Xiliang Army who don't know water into Fenshui, and feed them all the fish and shrimp in Fenshui!"

Han Xian heard Mrs. Guo's bold words, and immediately burst out laughing, Yang Feng, Hu Cai and others also echoed Mrs. Guo, and laughed together, as if the Xiliang army that took the initiative to attack, in their eyes, was already a headless corpse floating on the water of the Fen River.

When Mrs. Guo and the others were laughing, they didn't know that there was indeed a Xiliang army on the other side of Fenshui that had crossed Fenshui. Farther away, more soldiers were gathering by the river, their shouts resounding through the sky and converging into a torrent.

"The armor is ready, the war drums are urging people, Fenshui soup soup, strengthen the soul of our army!"