After Liu Zhang learned of Liu Bei's bad intentions, he decisively disposed of Zhang Song, and ordered that the documents of the generals guarding the pass should not be delivered to Liu Bei, and Liu Bei turned south and sent troops to attack Liu Zhang.

Later, when Liu Bei attacked Yucheng, the military advisor Pang Tonggong died.

【Go to War】

After Liu Zhang ordered the documents of the generals guarding the pass not to be sent to Liu Bei again, Liu Bei knew that his intention to seize Yizhou had been exposed, so he followed Pang Tong's advice and sent troops south.

At that time, Pang Tong persuaded Liu Bei: "Secretly select elite soldiers, travel quickly day and night, and attack Chengdu by taking small roads." Liu Zhang lacked the ability to lead the troops in battle, and he had never been on guard against it, so it was the best policy for our army to suddenly arrive and capture Chengdu in one fell swoop. Yang Huai and Gao Pei are famous generals under Liu Zhang, they rely on the strong forces in their hands, and they are stationed at Baishui Pass, I heard that they have written several times to persuade Liu Zhang, asking Liu Zhang to send you back to Jingzhou. When the general did not arrive at Baishui Pass, he first sent someone to inform them, saying that the situation in Jingzhou was critical and that he was ready to return to the army for rescue, and at the same time ordered the officers and men of our army to pack up and pretend that they were about to retreat. Yang and Gao both admired the general's fame, and were glad that you had evacuated Yizhou, and it was estimated that they would definitely come to pay their respects to the general lightly, and the general could take the opportunity to order them to be arrested, and then enter the customs to incorporate their army, and immediately wave their army to attack Chengdu, which is the middle policy. Retreat to the White Emperor City, contact the soldiers and horses of Jingzhou to enter Shu, and then slowly try to capture Yizhou step by step, this is the next policy. If you hesitate and stay here, you will inevitably fall into a serious predicament, and you must not delay it for so long. ”

After Liu Zhang killed Zhang Song, the best policy proposed by Pang Tong was no longer feasible, so Liu Bei adopted the middle strategy proposed by Pang Tong, summoned Liu Zhang's Baishui Pass overseer Yang Huai and others to come, accused him of being rude, beheaded him and Gao Pei, and turned south to attack Chengdu.

According to the "Book of Wei", in order to stimulate his subordinates, Liu Bei said: "We crusaded against strong enemies for Yizhou, and the soldiers worked hard and had no time to live in peace; And Liu Zhang's accumulated inventory is stingy with rewards and credits, and we only hope to fight to the death for him, is this possible! ”

Liu Bei then ordered Huang Zhong and Zhuo Ying to lead troops to attack Liu Zhang. And he led the army straight to Guanzhong, seized the wives and children of the Yizhou generals and soldiers as hostages, left Huo Jun to guard the rear, and then joined Huang Zhong, Zhuo Ying and others to march towards Fuxian County and occupy Fuxian County.

In the face of Liu Bei's betrayal, Yizhou engaged in Zheng Du to persuade Liu Zhang: "Now although Liu Bei led a lone army to attack us, the people have not yet surrendered to him, and they all rely on temporary collection of grain and grass from the people, and the army is seriously short of materials. The best strategy to deal with them is to move all the people of Brazil and Zitong to the west of Fushui, burn all the grain in the fields and granaries there, build high fortresses and dig deep ditches, and calmly wait for their arrival. When they come, they challenge us, but we can't hold out, and after a long time, they will cut off the supply of food and grass, and within a hundred days, they will surely retreat on their own. As soon as the other army retreated, our army pursued it, so that Liu Bei could be captured alive. ”

It is said that Liu Bei was very angry when he heard the news and asked Fa Zheng how to deal with it. Fa Zheng said: "Liu Zhang will not listen to Zheng Du's strategy in the end, and the general does not have to worry." As Fa Zheng expected, Liu Zhang said to his subordinates: "I have only heard of sending troops to resist the enemy to protect the people, but I have not heard of moving the people to avoid the enemy." So Zheng Du was dismissed, and Fucheng was captured by Liu Bei.

【Huo Jun Guards】

In the seventeenth year of Jian'an (212), when Liu Bei attacked Liu Zhang in the south of the Hui army, he left Huo Jun to guard Jiameng City. After Zhang Lu learned about it, he sent Yang Bo to lure Huo Jun to defend the city together in an attempt to capture Jia Meng, Huo Jun knew that there was a deception, and said to Yang Bo: "You can get my head, but you can't get this city." Yang Bo had no choice but to retreat.

From the record of "Zhang Lu sent Yang Bo to lure Jun and seek to defend the city together", it can be seen that Liu Bei is likely to have been in contact with Zhang Lu in secret, but when Liu Bei was preparing to seek Yizhou, it was not normal for this kind of thing to actually exist.

Later, Liu Zhang sent more than 10,000 people to lead more than 10,000 people, besieged Jia Meng by Langshui, in an attempt to cut off Liu Bei's rear, at that time, Jia Meng City was Liu Bei's only base in Shu at that time, but Huo Jun led the soldiers to hold on, and failed to capture it for a year, in fact, Huo Jun soldiers in Jia Meng City were only hundreds. Instead, Huo Jun took advantage of the other party's fatigue to select the elite, waited for the opportunity to attack, broke Liu Zhang's army, and took the opportunity to behead Xiang Cun.

[War Expands]

In order to resist the southward advance of Liu Bei's army, Liu Zhang sent his generals Zhang Ren, Liu Bi, Leng Bao, Deng Xian, Wu Yi and others to lead troops to fight Liu Bei's army in the area of Fuxian, but they were all defeated by Liu Bei, and the armies retreated to Mianzhu. Among them, Wu Yi also led the army to surrender to Liu Bei and was appointed as a rebellious general.

After conquering Fucheng, Liu Bei was a soldier, drinking and having fun, and he was full of ambition. He took advantage of the wine and said to Pang Tong: "Today's banquet should be soon." Pang Tong said: "Treating the crusade against other countries as pleasure is not a soldier of benevolence." When Liu Bei was drunk, he said angrily: "King Wu is slashing, singing and dancing before and after, isn't he a teacher of benevolence and righteousness?" You don't speak well, get out quickly. So Pang Tong got up and withdrew. But Liu Bei immediately regretted it and asked him to come back. Pang Tong returned to his original position and sat down, did not look at Liu Bei, did not apologize, and only cared about eating and drinking himself. Liu Bei asked, "Whose fault was it that we discussed just now?" Pang Tong said: "You and I are both at fault." Liu Bei laughed, and the joyful atmosphere at the banquet resumed.

In the eighteenth year of Jian'an (213), after the fall of Fucheng, Liu Zhangjia sent Li Yan to supervise the various armies in Mianzhu, but he did not expect Li Yan to directly lead the people to surrender to Liu Bei. Liu Bei's forces were stronger, so he assigned generals to pacify the subordinate counties, and at the same time mobilized Zhuge Liang, Zhang Fei, Zhao Yun and others in Jingzhou to lead the troops up the river, pacifying the White Emperor, Jiangzhou, and Jiangyang, leaving only Guan Yu to guard Jingzhou, and the war between Liu Bei and Liu Zhang was further expanded.

At that time, Zhang Fei, Zhuge Liang, Zhao Yun and others led Jingzhou soldiers into Sichuan for reinforcements. The army arrived in Jiangzhou first, Jiangzhou guard Yan Yan did not surrender, Zhang Fei broke it, occupied Jiangzhou, and captured Yan Yan alive, Zhang Fei shouted to Yan Yan: "The army is coming, why don't you surrender and dare to fight with me!" ”

Yan Yan returned: "You have unreasonably invaded our territory, we only have a decapitated general here, not a surrendered general!" Zhang Fei was furious, and ordered him to be beheaded, and Yan Yan said loudly without changing his face: "Beheading, beheading, what are you angry about!" Yan Yan's pride in refusing to surrender moved Zhang Fei, who released him and invited him as a guest.

After Zhang Fei and others broke through Jiangzhou, they swept Xichuan with Zhuge Liang and Zhao Yunbing in three ways, Zhao Yun pacified Jiangyang, Qianwei and other counties, and Zhang Fei pacified Ba County and Brazil County. In the end, the combined forces surrounded Chengdu and converged with Liu Bei.