The Three Kingdoms become stronger when they get treasures

Chapter 433 Blowing up Nanzheng
The dust has settled on the Huainan battlefield, and the Hanzhong battlefield has just begun to reach its climax.

After planning to ambush Cao Hong, Xu Shu finally gathered his army at Dingjun Mountain, prepared food and grass, and marched towards Nanzheng.Guo Huai and Xia Houshang couldn't resist, so they abandoned their camp and retreated into the city.

Although the Hanzhong Basin is surrounded by mountains, its interior is relatively flat. It is known as the Hanzhong Plain. It has been known as "National Treasure Tianfu, Land of Fish and Rice" since ancient times.The Hanzhong Basin covers an area of ​​about 5000 square kilometers, of which the Hanzhong Plain covers an area of ​​about 1400 square kilometers. It has a warm and humid subtropical climate, with an annual average temperature of 14 to 15 degrees Celsius.

The average annual rainfall here is about 900 mm, the river is not frozen, there is no snow in winter, there is little frost damage, the wind is small, the cultivated land is concentrated, and irrigation is convenient, so it is very conducive to the growth of rice, wheat and other crops.

The great ancestor Liu Bang made his fortune in the Hanzhong Basin, and Zhang Lu ruled Hanzhong for many years. In history, Zhuge Liang also relied on the grain output of Hanzhong for several Northern Expeditions. Therefore, taking Hanzhong will not only make Yizhou safer, but also get a very good grain production area. .

In this era, food is the most important thing in war. As long as you have food in your hands, there will be no shortage of people who will serve you. If you don’t have food, no matter how many soldiers you have, you can’t fight a big battle.

After passing Dingjun Mountain, the road to Nanzheng is basically unimpeded.Nanzheng is located in the southwest of the Hanzhong Basin, bordering the Hanshui River in the north and Bashan Mountain in the south. It was once the capital of Liu Bang when he was King of Han.

Xu Shu mobilized the entire force of Yizhou, gathered [-] troops, and countless counselors and generals. He wanted to capture Nanzheng in one fell swoop before Cao Jun's reinforcements arrived, and then defend Hanzhong.

In order to prevent the Cao army in Liangzhou from supporting Nanzheng, Xu Shu left Ma Chao and Ma Dai with the recruited Di and Qiang mixed light cavalry brigade to operate in Wudu.Due to the prestige of the Ma family in Liangzhou and Ma Chao's prestige, Cao Jun in Liangzhou was not only unable to send troops to rescue Hanzhong, but was disturbed and tired of coping.

And Zhang Yun, who was stationed at Yangping Pass, did not dare to give up the pass and go to Nanzheng, otherwise Cao Jun in Hanzhong would become a dog locked in the gate, and reinforcements would not be able to enter.

At this time, there were [-] Cao troops in Nanzheng City. The chief general was Cao Hong, the other generals were Cao Xiu, Xia Houshang, Han Hao, etc., and the advisers were Du Xi and Guo Huai.Although Cao Jun has few soldiers, they are all elite. There are still many people in Nanzheng City. Du Xi and Guo Huai are also quite resourceful, Cao Hong and Cao Xiu are also quite courageous, and there is no shortage of food in the city. Hope to hold out until reinforcements arrive.

How did Liu Bei obtain Nanzheng in the original book?It's very simple. Cao Cao led his troops to fight Liu Bei in Hanshui. He wanted to defeat this defeated general again, but was attacked by Zhang Fei and Wei Yan from behind and occupied Nanzheng.

It can be said that the Battle of Hanzhong was the most glorious moment in Liu Bei's life. For the first time in his life, he led an army to defeat Cao Cao head-on. Of course, there must be credit for his personal staff, Fa Zheng.

Now Cao Hong will definitely not go out of the city to fight. Although Xu Shu has more troops than Cao Hong, a big city like Nanzheng is a meat grinder for the attackers. Even if all the [-] troops are used up, they may not be able to win. Come down, because Cao Hong will definitely fight to the death.

But Xu Shu had a secret weapon. After Zhang Wu determined the strategy of Haohanzhong, he ordered a large amount of gunpowder to be transported to Yizhou and stored in Jiameng Pass.Xu Shu planned to imitate the original Battle of Moling and blow down the walls of Nanzheng City, so he had to ambush Cao Hong first and then attack the city, so that when he attacked the city, Cao's army would not have the strength to leave the city to counterattack.

There are two ways to use gunpowder to blow up a city.

The first way is to send soldiers to risk their lives to dig a hole under the opponent's wall, and then pile gunpowder inside and ignite it.This method is simple and crude, but it is relatively difficult to implement. It is necessary to send soldiers to attack the city regardless of casualties to provide cover for the blasting team, and to suppress the opponent with long-range firepower.

But the possibility of failure is also relatively high. If the enemy discovers its intention and launches rockets to block it, the gunpowder may not only fail to explode the opponent, but also kill one of the own people.Moreover, Xu Shu didn't have much gunpowder in his hands, so he could only succeed but not fail, otherwise he would have to use his life to attack by force.

The second way is to dig a tunnel, which can be dug under the opponent's wall without anyone noticing, and then blast in the tunnel.The disadvantage of this method is that it is relatively slow. In this era, there are no excavators or electric drills. If you encounter a big rock blocking the way when you are halfway through the digging, it will be laborious.

Hanzhong is surrounded by mountains, and Nanzheng is also very close to Bashan Mountain. There may be many stones buried in the soil under the feet. If there is a delay, Cao Jun's reinforcements will come.

After thinking about it, Xu Shu discussed with Fazheng and others for a while, and decided to use the method of digging tunnels, because although the first method is simple and direct, the probability of failure is too high. The enemy was set off, but there was no spare gunpowder.

Of course, digging tunnels cannot be completely kept secret without being noticed by the enemy.Soldiers defending the city in ancient times also had a way to deal with the attacking party digging tunnels. They would dig a hole near the corner of the city and put a special thin tank. , monitor the movement of the enemy.

This detection method has a certain scientific basis, because when the enemy army digs a tunnel with a hoe, it will make a sound. This sound travels fast underground, the sound wave attenuation is small, and it is easy to resonate with the cylinder, so the enemy can be detected. The location and distance of the army.

However, the general tunnel-digging tactic is to dig a tunnel leading to the city, and then send troops to sneak into the city to carry out a sneak attack. Therefore, if the enemy finds out the location of the tunnel, the enemy will flood it with water or set fire to it.

And Xu Shu just wanted to dig a tunnel under the Nanzheng city wall. It didn't matter even if Cao Jun detected the location, unless they dared to go out of the city to destroy it.

Digging a tunnel is a technical job, and time is very tight. It is impossible to just dig anywhere.

The so-called professional things should be done by professional people. Although there are not many professional geologists in this era, many scholars and literati have extensive knowledge, and many people understand this knowledge.

For example, Zhang Song, the governor of Yizhou, had a photographic memory and could memorize things backwards and forwards. He was truly a god.This guy once hand-drawn the "Geographical Map of Xichuan" and mapped all the dangerous places in Yizhou. How could he do this without any knowledge of geography?
In addition to Zhang Song, there are also several university scholars in Yizhou, such as Yang Hong and Qin Mi, who are well-read in poetry and books, and have a lot of knowledge, and they have studied astronomy and geography.Xu Shu also sent people to find the descendants of Li Bing who built Dujiangyan back then. In this era, family knowledge is generally passed down from generation to generation, and Li Bing's descendants must have studied geology.

(End of this chapter)