Cao Cao led an army to attack Hanzhong, defeated Hanzhong generals Yang Ren and Yang Ang all the way, and beheaded Zhang Lu's younger brother Wei Zhang. With the help of the mole, Zhang Lu was forced to surrender and Hanzhong was captured.

Liu Bei was afraid that Cao Cao would get Hanzhong and invade Xichuan from the south, so he contacted Sun Quan. Ask him to send troops to Hefei to harass Cao Cao's rear.

Zhang Liao, who was guarding Hefei, turned to Cao Cao for help. At the same time, he used Sun Quan's underestimation to defeat Wu Bing, and almost took Sun Quan alive, temporarily alleviating the crisis in Hefei.

When Cao Cao learned about it, he quickly gave up the idea of invading Shu. While sending Cao Hong, Xia and Zhang He to keep Hanzhong, he personally went to save He Fei, and Liu Bei found peace for a while.

Extended data:

Twenty years of Jian 'an is an opportunity for Cao Cao to unify the world. This year, Cao Cao successfully pushed back Zhang Lu, a separatist force in Hanzhong, after pacifying Ma Chao, Han Sui and other western cool governors. Hanzhong is the gateway of Shu. Only when Hanzhong is captured can Shu progress.

However, in this year, Cao Cao made an inexplicable move. After taking Hanzhong, his squad returned to the DPRK, leaving only Xia, Zhang He and others stationed in Hanzhong.

While Cao Cao occupied Hanzhong, Liu Bei also forced Zhang, a separatist regime, to occupy Shu. At this time, Ye Liu, Cao Cao's counselor, suggested that Liu Bei should win Hanzhong in one fell swoop while his foothold in Shu was unstable, but Cao Cao refused Ye Liu's suggestion and chose to move troops back to the DPRK.

Because of this, Liu Bei got a breathing space. After Cao Cao left, he attacked Hanzhong and killed Xia.

References:

Baidu encyclopedia-Hanzhong battle

References:

Baidu encyclopedia-look at Delong's Shu