Such a huge project took no more than half a month, and Zhu Si dug an isolation trench along the old moat in the south, west, and north of Kaifeng City. The so-called moat, in fact, is the former site of the outer city of Bianliang in the Song Dynasty, which was destroyed by the battle of Bianliang when the Jin soldiers invaded the Song Dynasty, and it was not repaired until the end of the Ming Dynasty. It is ironic that Zhu Si built an isolation trench along the destroyed outer city of Bianliang for the descendants of the Jurchens. The Jin soldiers invaded the Song Dynasty and besieged the two emperors of Huiqin in Bianliang City, forcing the two emperors to surrender. Today, Zhu Si surrounded the descendants of the Jurchens in the former capital of the Great Song Dynasty, and dug an isolation trench four feet deep and seven feet wide, perhaps it was another reappearance of the old things, but it was a pity that it was the Jurchens who were surrounded this time.

The project outside Kaifeng is in full swing, so that Dolgon and Zilharang in the city are like pins and needles. The two bigwigs stood at the head of the city, and Dolgon said to Zilharang: "Is Zhu Youlang crazy and wants to surround all the main forces of my Manchurian Eight Banners?" Zilharang said: "If we are not prepared for a decisive battle with them in Kaifeng, and we are not willing to retreat to the north of the Yellow River, then we will have to wait for this madman to bury us all here." At present, the deep trench of the Ming army is still unfinished, and if you want to evacuate, you can still have time to evacuate. ”

Dolgon was noncommittal about whether to evacuate or not, and someone came to report him, and Mandahai returned. Dorgon roared angrily and said, "Bring him up." When Mandahai came to Dolgon, a layer of hair had grown on his forehead, a thick layer of mud on his face, and his cotton armor had been scraped into tatters by branches, and he was decadent and embarrassed in two words.

"You're still willing to come back! What about your army of forty thousand? Man Dahai was asked by Dolgon, and immediately hugged Dolgon's thigh and shouted: "Uncle, my nephew is really nine deaths......" Man Dahai told the whole process of the battle of Xiayi, and how he escaped in the end, and got lost in a hurry and ran to Taihang Mountain for many days, all of which were told in detail, which can be described as a painful history of revolutionaries, listening to Dolgon and Zilharang's faces blushing and white.

Jilharang couldn't help but gasp and said: "40,000 cavalry were completely wiped out in half a day, even the main force of my army is difficult to do." Today's Ming army, whether it is the rapid increase in the size and combat effectiveness of their cavalry, or the tactics of these newly formed infantry, make us very uncomfortable, and it is difficult for us to thoroughly understand their new tactics for a while. We lack sufficient grasp of the latest situation of the current Ming army, especially since the main force of the Ming army is currently in one place, and if we want to defeat them immediately, even if we can do it, we will have to pay an unbearable price. ”

Dolgon said in a sigh: "What Prince Zheng said is very reasonable, from the beginning of the battle of Salhu to the battle of Songjin, whether it is victory or defeat, our army's tactics and troop layout of the Ming army, and even the advantages and disadvantages of each general, have been mastered in too detail. But now, we are really too unfamiliar with the Ming army in front of us. ”

Yes, what Dolgon said is right, compared to Nurhachi's mastery of the intelligence of the Ming army back then, the current Dolgon knows almost nothing about the Ming army. After all, the old Han King has always been under the command of the border marshal Li Chengliang, and his mastery of the strategy and tactics of the Ming army is even more familiar than that of ordinary Ming army generals, and his understanding of Ming army generals is even more detailed. Romance

Under the wing of Li Chengliang, Nurhachi weaved a big net for the generals of the Ming army's Liaodong border army. Marriage, bribery, and all kinds of emotional cards are available, so his grandson-in-law Fu Shun Shou general guerrilla general Li Yongfang can easily give Fu Shunbai to him, and Li Rubai committed suicide in the end. If it weren't for the fact that a group of relatives such as Li Rubai and Li Yongfang, who were mastered by Nurhachi in the Ming army, sent accurate intelligence messages to Nurhachi in the Battle of Sarhu. How can Nurhachi do it, depending on how many ways you come, I will only go all the way? Are you kidding? Go ahead, and I'll get rid of your lair when I get back." Why did Li Rubai commit suicide in the end to maintain his reputation? Why did Nurhachi never attack Li Rubai in the Battle of Sarhu, and Li Rubai did not really want to carry out the military order to fight with Nurhachi, but immediately retreated as soon as there was a stir?

With this big net, the Houjin army could easily look down on the battlefield against the Ming army. But now Zhu Si has not only changed all this, changed most of the arms and structure of the Ming army, but also eradicated the vast majority of spies and surrender factions in Zhaoqing at one time. Jin Yiwei has never slackened his detection of the spy network planted by the Qing army in the Ming Dynasty, so that the Ming army attacked the northwest and attacked Denglai Erzhou by sea Dolgon knew nothing about such a large military move. In terms of intelligence warfare, the Ming army's re-victory, and the upgrading and change of the entire military command system, made the Qing army completely blind and deaf when fighting against the Ming army, just as the Jin army did to the Ming army later.

Intelligence warfare is the most lethal weapon on the battlefield, and military equipment is secondary. The so-called knowing oneself and knowing the other side will not be defeated in a hundred battles, Sun Tzu said in the fourth part of "The Shape of the Army": The good defender hides under the nine earths, and the good attacker moves above the nine heavens, so he can protect himself and win all. But if you can't destroy the enemy's intelligence network, how can you keep it and hide it under the Nine Lands? If you can't get the most accurate intelligence information, you can ambush the enemy but don't come; What if you attack a city ten times the enemy, only to find that the opponent's city is just an empty city or a large number of unknown defenders are hidden?

Only under the premise of information warfare can all the war platforms be systematically integrated, and Dolgon, who has become deaf and blind, heard that the Mandahai army had wiped out his 40,000 elite cavalry in less than a day, and he still had the confidence to fight a decisive battle with the main force of the Ming army outside the city?

With Mandahai's appearance, Zilharang strengthened his determination to flee north, and Dolgon was ready to retreat. No matter how many illusions may have about future victories, at this moment they must retreat. Not only did they have to retreat from Kaifeng, but they also had to take away the 40,000 horses under the command of Le Kedehun, the king of Shuncheng County, who was stationed in Luoyang. At present, there is only one question on the table of the princes, that is, how to go.

Although Dolgon was reluctant, his brain was not broken, and he still calmly said to Zilharang: "Even if we want to retreat, we should plan carefully. The current situation of Zhu Youlang surrounding us is very likely to be one of the three encirclement. He did not blockade the west of the city with a barrier for the time being, but only placed a large number of troops in the west of the city, perhaps in the hope that we would break through from the location he had planned. ”