In Jingzhou, Xu Shu's greatest contribution to Liu Bei was to recommend Zhuge Liang for him, and in order to invite Zhuge Liang, Liu Bei did not hesitate to deign to look at the thatched house, and Zhuge Liang's "Longzhong pair" was the basic strategic policy of the Shuhan Group in the future, and even a national policy.

【Longzhong Pair】

In the twelfth year of Jian'an (207) (Note 1), Liu Bei Longzhong went to visit Zhuge Liang, and went there three times in total before he saw him. At that time, Liu Bei told the people next to him to avoid it, and said to Zhuge Liang: "The rule of the Han family collapsed, Dong Zhuo and Cao Cao successively took power, and the royal family suffered to flee. I didn't measure whether my virtue could convince others, estimate whether my strength could win over others, and wanted to uphold justice for the people of the world, but I lacked resourcefulness, shallow knowledge, and had no way, so I failed and got into today's situation. But my ambition has not yet stopped, so could you please tell me what to do? ”

Zhuge Liang replied: "Since Dong Zhuo's rebellion, heroes have risen at the same time, turning states into counties, and there are too many to dominate one side. Compared with Yuan Shao, Cao Cao has low fame and fortune and few troops, but Cao Cao finally defeated Yuan Shao and defeated the strong with the weak, not only because of the good timing, but also because of the proper planning of people. Now Cao Cao has an army of one million and holds the emperor hostage to order the princes, which really can't compete with him. Sun Quan has occupied Jiangdong for three generations, the terrain is dangerous, the people are attached, and talented people are appointed, Sun Quan can use him as foreign aid in this regard, but not seek him. Jingzhou is north of the Han River, the water of the water, all the way to the South China Sea materials can be used, the east and Wu County, Huiji County connected, the west and Ba County, Shu County communication, this is the land of soldiers, but his master Liu Biao has no ability to hold it, this is probably the heaven to use it to fund the general, did the general not have the intention of seizing it? Yizhou has a dangerous terrain, a vast and fertile land, superior natural conditions, abundant products, and a solid form, and Gaozu established the imperial industry with it. Liu Zhang was mediocre and cowardly, and Zhang Lu threatened him in the north, where the people were prosperous and rich, but Liu Zhang did not know how to cherish them. Talented people aspire to a wise monarch. The general is not only a descendant of the royal family, but also has a high prestige, is famous all over the world, widely recruits heroes, longs for talents, and is hungry and thirsty, if he can occupy the two prefectures of Jing and Yi, hold the dangerous places, make peace with the various ethnic groups in the west, and appease the ethnic minorities in the south, unite Sun Quan externally, and reform politics internally; Once the situation in the world has changed, send a general to lead the army of Jingzhou to kill the two counties of Wan and Luo, and the general will personally lead the army of Yizhou to fight Qinchuan. If this can really be done, then the cause of hegemony can be successful, and the Han family can be revived. ”

Liu Bei said: "Okay! Since then, the relationship with Zhuge Liang has deepened day by day.

Seeing Liu Bei so important to Zhuge Liang, Guan Yu, Zhang Fei and others were not happy, Liu Bei explained to them: "I have Kong Ming, just like a fish has water." I hope you don't say anything against it. Guan Yu and Zhang Fei calmed down.

【Three-point World】

Zhuge Liang first analyzed the specific situation at that time in detail in "Longzhong Pair", which directly explained that Cao Cao at that time was no longer able to compete with him, and Sun Quan was deeply rooted, and he was not the object of Liu Bei's seizure, but a foreign aid that Liu Bei needed to win over as much as possible. And Liu Bei needs to seize the target is Jingzhou and Yizhou, after occupying these two large states, he will contact Sun Quan, demand politics internally, resist Cao Cao, and finally choose the opportunity to go north and seize the world.

First of all, Liu Bei's first step was to seize Jingzhou and Yizhou. Jingzhou extends in all directions, has been a place of military use since ancient times, and the Yangtze River is dangerous, which is a strategic place that Liu Bei needs to control. And Yizhou geography is dangerous, rich in products, easy to defend and difficult to attack, but also can be used as a base camp place, Jingzhou was facing Cao Cao in the north, Sun Quan in the east of the two strong enemy attack, has begun to have a weak heart, Liu Biao, the lord of the defense also appeared obvious decline, Jingzhou's loss at that time was inevitable, and Yizhou Liu Zhang's skills are average, not an excellent leader, his subordinates rebelled many times, and it seems that it is not difficult to seize Yizhou from his hands.

After Liu Bei captured Erzhou, the second step was to wait. Because of the strength of Cao Cao's group in the north, it is not so simple to defeat Cao Cao and restore the Han family, you need to stabilize your own territory and enhance your strength, Liu Bei must digest the two states before he can have the strength to go north, but the power of the two states in the south alone is still not the opponent of the Cao Wei group at that time, so Liu Bei must wait for an opportunity, an opportunity that is enough for the world to change.

The last step is the Northern Expedition, Zhuge Liang here not only emphasized that the two armies went north at the same time from Jingzhou and Yizhou, echoing each other, and the two armies went north at the same time, but also made it clear that the premise of the Northern Expedition was that there must be turmoil in the north, and there were enough opportunities to take advantage of, and the implication was not to do it if there was not enough time.

In addition, there is a thing that needs to be done from beginning to end in the "Longzhong pair", which is to contact Sun Quan, because after Liu Bei occupied Jingzhou and Yizhou, the Yangtze River natural danger was shared by Liu Bei and Sun Quan, Liu Bei could use the Yangtze River to fight against Cao Cao, but it was a joke to deal with Sun Quan, who was better at the naval army, and more importantly, Sun Quan was on the east side of Liu Bei, and Liu Bei had to deal with the relationship with Sun Quan if he wanted to have a stable rear in the south.

In the "Longzhong pair", the concept of Wei, Shu and Wu dividing the world was also initially proposed, Zhuge Liang's plan was that Liu Bei's group occupied Jingzhou and Yizhou, Sun Quan occupied Jiangdong, and the north was Cao Cao.

And when Zhuge Liang proposed "Longzhong Pair" for Liu Bei, Zhuge Liang was just a twenty-six-year-old young man, and Liu Bei was not a down-and-out person who was nearly fifty years old and had nothing to do.

Then everyone is familiar with history, Liu Bei achieved the great cause of the emperor, and Zhuge Liang is considered to be a famous appearance through the ages.

[Three Kingdoms Era "Four Pairs"]

"Longzhong pair" is the last "pair" after "Jizhou pair", "Jiangdu pair", and "couch pair". He was the latest to appear and had the greatest historical influence.

"Jizhou pair" is the strategic policy of Yuan Shao Group in the north, "Jiangdu pair" is the strategic guidance of Sun Ce Group, "couch pair" is the inheritance and development of "Jiangdu pair", and "Longzhong pair" is the future strategic plan of Liu Bei Group.

Note 1: I do not see a clear record of the time when Liu Bei went to see Zhuge Liang in the "Chronicles of the Three Kingdoms", and the time here is calculated based on the words in Zhuge Liang's "Leaving the Teacher's Table".