"Master Sun, that's all for today's lesson!" Without waiting for Sun Chengzong to speak, the young emperor had already announced that he would leave class, and asked the palace people to move the sand table and invite Sun Chengzong to watch it together.

Sun Chengzong was quite surprised when he saw the sand table at first glance, but when he looked carefully, it was the topography of Liaodong. Mountains, rivers, and cities are vividly visible, and you can see the situation of both the enemy and the enemy.

"This is made by the Ministry of War." Zhu Youxiao approached and said: "Due to the time limit, it is not completely detailed, but it can still be seen roughly." ”

Sun Chengzong nodded and praised: "Your Majesty is wise and intelligent, this is to follow the Eastern Han Dynasty general Ma Yuan's 'gathering rice for the valley, pointing to the situation', so that 'captured in the eyes'!" ”

Zhu Youxiao smiled, his face became serious, he took the wooden whip next to the sand table, pointed and said: "Master Sun, please look, this is Guangning, this is Dalinghe, this is Jinzhou, this is Ningyuan, this is Shanhaiguan ......"

Aside from Guangning, what Zhu Youxiao pointed out was the famous Guanning Jinfeng defense line in history, that is, Shanhaiguan to Jinzhou through Ningyuan.

The Guanning Jin defense line is divided into two sections in the north and south in history, the southern section is the Guanning defense line, which is about 100 kilometers long, from Shanhaiguan to Ningyuan; The northern section is the Ningjin defense line, which is also about 100 kilometers long, from Ningyuan through Lianshan, Tashan, Songshan, Jinzhou, and arrives at the Daling River.

The defensive line, as the name suggests, is a horizontal line that blocks the enemy's attack to protect the city and the people behind the line. For example, the Maginot Line, for example, the Hindenburg Line.

However, no matter how you look at the Guanning Jin defense line, it is a vertical line, which is a string of fortresses extending out, from Shanhaiguan to Jinzhou, a total of more than 400 miles. Now, add Quang Ninh, which is fighting fiercely.

Well, at that time, the Ming Dynasty established this line of defense not for pure defense, but to push forward with fortress tactics.

When Ning Yuan was stable, he pushed it to Jinzhou; When Jinzhou is stable, it will be pushed to Guangning; When Guangning is stable, go to Shenyang. Push it straight to the door of Houjin's house, and then put Houjin in a nest.

This idea has the possibility of being realized, but Houjin is a dead man, and it will make you keep cultivating.

Therefore, in addition to swallowing gold and dragging down the economy of the Ming Dynasty, the historical Guanningjin defense line played a very limited role.

What should I do if I am cut off by the enemy, and what should I do if I am surrounded by the enemy?

In history, the Later Jin army occupied Jinzhou three times, and then retreated three times, wasting troops here at all.

On the contrary, it was the Ming Dynasty, in order to maintain the Guanning Jin defense line, taxes and taxes were raised, and civil unrest broke out.

Or because of the Guanningjin defense line, the battle of the Daling River, the elite of the Ming army outside the pass was lost; In the battle of Songjin, the elite of the nine sides was empty......

There is a serious imbalance between investment and returns, or even upside down, and the head is in water to make this loss-making transaction.

Neither has the ability to fight in the field with the Houjin army, and the enemy can only close the city and defend it when he comes to attack, allowing the enemy to wreak havoc and loot around the city, what offensive fortress can he talk about?

As for what recruited the Liao people to cultivate the fields to supplement the grain and straw of the Ming army stationed in Guanningjin, it was even more taken for granted.

As soon as the enemy comes, you retreat back to the city, and the people of Tuntian may be able to hide in the city, but aren't all the food you have worked so hard to grow given to the enemy in vain?

For example, in the battle of Ningyuan, Ningyuan City was defended, but more than 7,000 generals and seven or eight thousand merchants died on Juehua Island, and countless grains and grass materials were looted.

All in all, in short, Zhu Youxiao already had a plan to abandon Guangning and Jinzhou and retreat to Ningyuan.

Since Houjin doesn't care about the Ningjin area, it means that this place is not that important. To put it bluntly, the so-called reconquest of lost land is nothing more than the reception of the no-man's land between the two armies.

Historically, Zhu Youxiao suspected that this was deliberately done by Hou Jin. Set aside such a large area and wait for the Ming army to come.

Didn't you build a city, repair it! Don't you want to garrison and store supplies, okay, okay!

When the Ming army was almost busy, the Houjin army also dispatched. Or besiege the city to send reinforcements, or rob, kill and destroy the city, and then pat the ass and leave.

Instead of sending people and materials, destroying and repairing, repairing and destroying, but only occupying a no-man's land of little value, and spending money to build a city and garrison, it is better to shrink directly to Ningyuan.

This plan is similar to Xiong Tingbi's "give up Liaodong and withdraw from the customs", but Ningyuan is added as a barrier to Shanhaiguan, which is equivalent to double insurance.

Although it is a step further than Xiong Tingbi's strategy, Zhu Youxiao also knows that it is not easy to implement.

Strategic contraction should be a good move, but on the other hand, it can also be said to be "losing land and retreating without a fight".

Therefore, Zhu Youxiao had to take into account public opinion, the morale of the army and the people, and the reactions of the ministers of the DPRK and China.

The theory of quick victory and rapid war is still very marketable in Daming, and it can even be said to be the mainstream of public opinion.

This is especially true of the ministers of the DPRK and China, either out of patriotic enthusiasm or simply not understanding the actual situation in Liaodong, clamoring for "exterminating thieves" every day, where can they accept the "traitorous" behavior of retreating without a fight?

Others don't say it, Sun Chengzong, who Zhu Youxiao wants to entrust with important tasks, is a supporter of the active attack. At the same time, Sun Chengzong was also the advocate and implementer of the fortress advancement, and the founder of the Guanningjin defense line.

Because of this, Zhu Youxiao wanted to reveal it sideways, and strive to make Sun Chengzong change his mind and become his real help.

It's just that at this time, Guangning is still in a big war, the outcome is unpredictable, Zhu Youxiao can't say too deeply, and Sun Chengzong can't be like a traverser, with a God's perspective.

"Your Majesty wants to implement Xiong Tingbi's tripartite arrangement strategy?" When Sun Chengzong heard the young emperor mention that the western part of Liaoning was light and the coastal area was heavy, he asked with some doubts.

Xiong Tingbi's tripartite arrangement was: Quang Ninh set up a barrier on the river with horse infantry, attacked the enemy with the situation of mountains and rivers, and pinned down all the enemy's forces;

Tianjin and Deng, Lai, set up a fleet of naval forces, and took advantage of the situation to break into the enemy's southern garrison and shake their military morale, so that the enemy would inevitably have internal worries, and Liaoyang could be recovered.

However, Zhu Youxiao's light Liaoxi and heavy coastal areas are somewhat different from the tripartite arrangement.

The most important point was that he wanted to abandon Guangning, and the area of hundreds of miles between Guangning and Ningyuan, and stationed heavy troops in Ningyuan and Shanhaiguan, and completely adopted a defensive posture.

The purpose of defense is to gain time, save money, retrain elite troops, and promote the good and eliminate the bad in internal affairs, with a view to counterattacking. This time will be relatively long, and Zhu Youxiao tentatively set it at five years.

The heavy coastal area is similar to Xiong Tingbi's, such as the establishment of naval armies in Tianjin and Denglai, and the harassment and attack of Houjin in the vast coastal area, making it exhaustive.

There is another point that Zhu Youxiao did not say, that is, Dongjiang opened the town and provided Dongjiang Town with as much food, weapons, and armor as possible, so that it could more effectively contain the Houjin army and make the Mao Da guerrilla captain more meritorious.

Some people may be concerned about Zhu Youxiao's strategic contraction.

The Ningjin defense line was there, but it could not be stopped, and the Jin army bypassed the Great Wall and raged in Gyeonggi. Shrinking to Ningyuan or Shanhaiguan, wouldn't it be more convenient for the Jin army to attack later?