Hanzhong Campaign The Hanzhong Campaign was a military campaign launched by the warlord Liu Bei to seize control of the of Hanzhong from his rival Cao Cao . The campaign took place between 217 and 219 during the prelude to the Three Kingdoms period . Liu Bei emerged victorious and took control of Hanzhong in 219 , subsequently declaring himself " King of Hanzhong " in autumn that year . Background . In 215 , Cao Cao attacked the warlord Zhang Lu in Hanzhong , defeating the latter at the Battle of Yangping . Zhang Lu surrendered and Hanzhong came under Cao Cao ' s control . On Liu Bei ' s side , he had also recently seized control of Yi Province ( covering present - day Sichuan and Chongqing ) from Liu Zhang , and was in the midst of a dispute with his ally Sun Quan over Jing Province ( covering present - day Hubei and Hunan ) . Liu Bei felt threatened when he received news that Hanzhong had fallen to Cao Cao , because Hanzhong was the northern " gateway " into Yi Province , and he was now in danger of losing his home base to Cao Cao . Hence , Liu Bei came to a border treaty with Sun Quan , who had seized Changsha ( 長沙 ) , Guiyang ( 桂陽 ) , and Lingling ( 零陵 ) from him . Liu Bei asked Sun Quan to divert Cao Cao ' s attention by attacking Hefei and demanded Lingling back . In return , he recognised Sun Quan ' s control over Jing Province ' s commanderies of Changsha , Jiangxia ( 江夏 ) and Guiyang . Strategic difference . In Hanzhong , Sima Yi and Liu Ye urged Cao Cao to use the opportunity to attack Yi Province , but Cao rejected the idea , saying , " We should not be discontent . Now that we ' ve already conquered Longyou ( referring to present - day eastern Gansu ) , you ' re still longing about merging Shu ( referring to Yi Province ) ! " Cao Cao then left his generals Xiahou Yuan , Zhang He and Xu Huang behind to defend Hanzhong , and his Chief Clerk ( 長史 ) Du Xi to oversee affairs in Hanzhong . In 217 , Liu Bei ' s advisor Fa Zheng analysed the reason Cao Cao left Xiahou Yuan to guard Hanzhong — the newly conquered Hanzhong was still unstable ( partly due to the massive relocation enforced by Cao Cao ) . Fa Zheng also believed Xiahou Yuan and Zhang He were not good commanders , so the pair could not defend the commandery . Hence , Fa Zheng urged Liu Bei to attack Hanzhong , stating three advantages if the commandery was in Liu ' s control : the ideal usage of Hanzhong was that it served as a base of operations to attack Cao Cao and revive the Han Dynasty ; a decent usage of Hanzhong was that Liu Bei could attack Yong and Liang provinces from it ( Hanzhong granted access to the two provinces ) and expand his territory ; a more conservative mean was that defense of Hanzhong could be a long - lasting strategy for the survival of the Shu regime . Liu Bei agreed to Fa Zheng ' s insight and ordered him to plan for the upcoming campaign . The campaign . Initial clashes . In 217 , Liu Bei followed Huang Quan ' s strategy and defeated the enemy generals Pu Hu ( 朴胡 ) and Du Huo ( 杜濩 ) , taking control of Badong ( 巴東 ) and Baxi ( 巴西 ) commanderies , which were respectively guarded by them previously . Liu Bei ' s army then advanced towards Yangping Pass ( 陽平關 ) near Hanzhong . At the same time , Liu Bei also sent Zhang Fei , Ma Chao , Wu Lan ( 吳蘭 ) , Lei Tong and Ren Kui ( 任夔 ) to attack Wudu ( 武都 ) commandery , and they garrisoned at Xiabian ( 下辨 ) . During this time , Lei Ding ( 雷定 ) of the Di ethnic group led seven tribes to join Liu Bei . As for Cao Cao ' s side , Xiahou Yuan defended Yangping Pass , Zhang He and Xu Huang respectively guarded Guangshi ( 廣石 ) and Mamingge ( 馬鳴閣 ) , while Cao Hong and Cao Xiu led a separate force to resist Zhang Fei . In 218 , Zhang Fei and Ma Chao ' s army garrisoned at Mount Gu ( 固山 ) , where they spread news that they were going to blockade the enemy ' s retreat route . Cao Hong wanted to attack Wu Lan at Xiabian , but the other generals were suspicious of Zhang Fei ' s movements . Cao Xiu thought that if Zhang Fei was really planning to seal their retreat route , he should keep his plan covert ; now that Zhang Fei had overtly revealed his intention , they should make use of the opportunity to feign retreat and perform a frontal assault . Cao Hong consented to Cao Xiu ' s tactic and attacked . Lei Tong and Ren Kui were killed in battle , while Wu Lan fled to join the Di tribes , where he was subsequently killed by a Di leader , Qiang Duan . After such a defeat , Zhang Fei and Ma Chao withdrew their army by the third lunar month . On another front , Liu Bei was facing Xiahou Yuan at Yangping Pass . In the seventh lunar month , Liu Bei sent Chen Shi to attack Mamingge , but the latter was defeated by Xu Huang , and some of the fleeing soldiers fell into the deep valleys during their escape . Liu Bei personally led an assault on Zhang He at Guangshi but was unable to overcome his enemy . He then sent an urgent letter to Zhuge Liang in his capital , Chengdu , requesting for reinforcements . Zhuge Liang vacillated and consulted Yang Hong ( 楊洪 ) , who said , " Hanzhong is the throat of Yi Province . This is a critical point of survival and destruction . Without Hanzhong there will be no Shu ( Yi Province ) . A disaster has befallen on the gates of our home . At this moment , the men should go to war , the women should help in transporting supplies , what ' s there to hesitate about sending reinforcements ? " Zhuge Liang accepted Yang Hong ' s advice and sent a relief force to Liu Bei , as Liu Bei continued his standoff against Cao Cao ' s forces . Turn of the tide . In the ninth lunar month of 218 , Cao Cao moved from Ye City to Chang ' an near Hanzhong to direct the defence against Liu Bei , but had been held up by internal problems including a major coup d ' état and some local uprisings . In the meantime , Liu Bei and Xiahou Yuan had been locked in a stalemate for a year . In the first lunar month of 219 , to break the deadlock , Liu Bei crossed the Mian River ( 沔水 ) south of Yangping Pass and advanced towards Hanzhong through the mountains . Liu Bei ' s army set up camp at Mount Dingjun . In response , Xiahou Yuan and Zhang He led their forces out in an attempt to take control of higher ground , and they made camp at Zouma Valley ( 走馬谷 ) . During the night , Liu Bei followed Huang Quan ' s plan and set fire to the enemy camp fences . Xiahou Yuan led a force to defend the southern flank while sending Zhang He to guard the eastern side . Liu Bei launched a direct assault on Zhang He and Zhang started to falter , so Xiahou Yuan despatched half of his forces to support Zhang . At this point , Fa Zheng told Liu Bei that it was an opportune time to attack . Liu Bei ordered his men to shout loudly and beat the drums , and sent Huang Zhong to charge at the enemy . The mettlesome soldiers of Huang Zhong broke through the enemy lines and slew Xiahou Yuan and Zhao Yong ( 趙顒 ) , while Zhang He fled with his surviving troops to north of the Han River , where they set up camp . As Cao Cao ' s forces had just lost their commander , Xiahou Yuan , a tempest ensued . Du Xi and Guo Huai regrouped their scattered troops and ( unofficially ) nominated Zhang He to replace Xiahou Yuan . Zhang He accepted and gave orders to his troops , restoring peace and order in his army . The following day , Liu Bei planned to cross the Han River and attack Zhang He , whose officers pointed out they were outnumbered , and suggested to Zhang to set up camps along the Han riverbank . Guo Huai felt that their forces were displaying weakness to the enemy by doing so , he proposed setting up camp far away from the river to lure the enemy to cross the shallow , during which they counterattack the enemy . Zhang He agreed with Guo Huai ' s idea and moved his camp further away from the river . Liu Bei became suspicious and did not dare to cross the river . In Chang ' an , when Cao Cao heard that Xiahou Yuan had been killed in action , he despatched Cao Zhen with an army to reinforce their forces at Yangping Pass . When Cao Zhen arrived , he directed Xu Huang to attack Liu Bei ' s general Gao Xiang . Xu Huang scored a victory and temporarily restored some morale for Cao Cao ' s side . Battle of Han River . In the third lunar month of 219 , Cao Cao personally led an army from Chang ' an to Hanzhong via Xia Valley ( 斜谷 ) . Liu Bei was not worried , as he thought , " Even if Cao Cao came , he cannot do anything . I ' ll definitely take control of the Han River . " Hence , Liu Bei gathered his forces and put up a firm defence , refusing to engage Cao Cao ' s army . Later , when Cao Cao ' s forces were transporting supplies via Beishan ( 北山 ) , Huang Zhong led a force to rob the enemy ' s supplies , but had yet to return on time . Zhao Yun led ten horsemen out of camp in search of Huang Zhong and encountered Cao Cao ' s army . They were surrounded but Zhao Yun fought his way out and retreated back to camp with the enemy in pursuit . Upon reaching camp , Zhao Yun ordered the gates to be opened , flags and banners to be lowered , and the beating of war drums to be stopped . Cao Cao ' s men feared an ambush in the camp and turned back . Just then , Zhao Yun ordered his troops to beat the drums loudly and his archers to rain arrows on the enemy . Cao Cao ' s soldiers were thrown into confusion and trampled on each other as they attempted to flee , while many drowned as they tried to escape across the Han River . As Cao Cao had been in a standoff against Liu Bei for several months and had been facing serious logistics problem , he eventually gave an order , " chicken rib " ( 雞肋 ) . Cao Cao ' s men were puzzled as they did not understand what " chicken rib " meant , except for Cao Cao ' s registrar Yang Xiu . Yang Xiu explained that it was a pity to discard chicken ' s rib , even though it did not have much meat to be eaten . This was an analogy to the situation Cao Cao was facing : Cao knew that he had little chance of defeating Liu Bei , but felt that it was a pity to just relinquish Hanzhong and withdraw . By the fifth lunar month , Cao Cao retreated back to Chang ' an and gave up Hanzhong to Liu Bei . Aftermath . A month after successfully conquering Hanzhong , Liu Bei sent Meng Da to attack Fangling ( 房陵 ) via Zigui ( 秭歸 ) . Meng Da defeated and killed Fangling ' s Administrator , Kuai Qi ( 蒯祺 ) , and took control of the area . Liu Bei later sent his adopted son , Liu Feng , to attack Shangyong ( 上庸 ) via sailing down the Mian River ( 沔水 ) from Hanzhong . Shangyong ' s Administrator Shen Dan ( 申耽 ) surrendered to Liu Feng . In the seventh lunar month of 219 , Liu Bei declared himself " King of Hanzhong " . On the other hand , after withdrawing , Cao Cao was worried that Liu Bei might attack Wudu ( 武都 ) commandery , so he ordered the Inspector ( 刺史 ) of Yong Province , Zhang Ji , to relocate 50 , 000 Di people from Wudu to Fufeng ( 扶風 ) and Tianshui ( 天水 ) commanderies .