Liu Bei's takeover of Yi Province was a military campaign by the warlord Liu Bei in taking control of Yi Province (covering present-day Sichuan and Chongqing) from the provincial governor, Liu Zhang. The campaign took place between the years 211 and 214 in the late Eastern Han dynasty; although the conflict between Liu Bei and Liu Zhang started in January or February 213 when the latter discovered the former secret communications and subsequently executed Zhang Song. It concluded with victory for Liu Bei and his successful takeover of the province from Liu Zhang in July 214. Yi Province would serve as the foundation of the state of Shu Han during the Three Kingdoms period.
Background
After the Battle of Red Cliffs, Sun Quan invited Liu Bei to take Yi Province with him, but the latter strongly rebutted the former, saying: "if you're going to conquer the land of Shu, I will loosen my hair and become a hermit in the deep hills. Earth under Heaven can hear my promise, and I'll live up to my words!"((孫權)遣孫瑜率水軍住夏口。備不聽軍過，謂瑜曰：「汝欲取蜀，吾當被發入山，不失信於天下也。」) Sanguozhi vol. 32. Believing Liu Bei, Sun Quan aborted his plan; however, Liu Bei was actually trying to take Yi Province for himself and negotiated Yiling County and Nan Commandery from Sun Quan. In 211, Liu Zhang, the Governor of Yi Province, heard that Cao Cao was planning to attack Zhang Lu in Hanzhong Commandery. As Hanzhong Commandery was a strategic location and the "gateway" into Yi Province, Liu Zhang sent Fa Zheng to form an alliance with Liu Bei after Zhang Song convinced him to do so. Liu Bei then led his men to Yi Province under the pretence of helping Liu Zhang conquer Hanzhong Commandery.(十六年，益州牧劉璋遙聞曹公將遣鍾繇等向漢中討張魯，內懷恐懼。別駕從事蜀郡張松說璋曰：「曹公兵強無敵於天下，若因張魯之資以取蜀土，誰能御之者乎？」璋曰：「吾固憂之而未有計。」松曰：「劉豫州，使君之宗室而曹公之深讎也，善用兵，若使之討魯，魯必破。魯破，則益州強，曹公雖來，無能為也。」) Sanguozhi vol. 32.
The campaign (211–214) Takeover of Jiameng (211–213) In 211, Liu Bei led an expedition force of tens of thousands of soldiers into Yi Province after leaving behind Zhuge Liang, Guan Yu, Zhang Fei and Zhao Yun to guard Jing Province.(先主留諸葛亮、關羽等據荊州，將步卒數萬人入益州。) Sanguozhi vol. 32. When Liu Bei entered Yi province, it was as if he was returning home. When he arrived at Fu County (涪縣; in present-day Fuling District, Chongqing) Liu Zhang led 30 000 soldiers in a flambloyant display to welcome Liu Bei warmly; it was the occasion of a great meeting where they feasted for more than 100 days. Liu Zhang provided Liu Bei with more provisions and equipment for his army before they parted ways.(敕在所供奉先主，先主入境如歸。先主至江州北，由墊江水 詣涪，去成都三百六十里，是歲建安十六年也。璋率步騎三萬馀人，車乘帳幔，精光曜日，往就與會；先主所將將士，更相之適，歡飲百馀日。璋資給先主，使討張魯，然後分別。 ) Sanguozhi vol. 31.
During this meeting; Fa Zheng told Liu Bei that Zhang Song along with Pang Tong wanted to use this opportunity to capture Liu Zhang and force him to hand over Yi Province; however Liu Bei didn't follow this plan because he felt that the plan was too hasty and that he should first win the hearts of the people of Yi province.(至涪，璋自出迎，相見甚歡。張松令法正白先主，及謀臣龐統進說，便可於會所襲璋。先主曰：「此大事也，不可倉卒。」) Sanguozhi vol. 32. Many of Liu Zhang's retainers protested against his decision to invite Liu Bei into the Yi province. Among them were Liu Ba(璋遣法正迎劉備，巴諫曰：「備，雄人也，入必為害，不可內也。」既入，巴復諫曰：「若使備討張魯，是放虎於山林也。」璋不聽。巴閉門稱疾。) Lingling Xianxian Zhuan annotation in Sanguozhi vol. 39. and Huang Quan(璋主簿黃權陳其利害，... 璋一無所納，敕在所供奉先主，先主入境如歸。) Sanguozhi vol. 31. with Wang Lei (王累) committing suicide.(從事廣漢王累自倒縣於州門以諫，) Sanguozhi vol. 31. Yan Yan famously remarked that Liu Zhang's decision was the equivalent of setting a tiger free to defend himself.(初，先主入蜀，至巴郡，顏拊心歎曰：「此所謂獨坐窮山，放虎自衞也！」) Huayang Guo Zhi annotation in Sanguozhi vol. 36.
Liu Bei's army totalled more than 30,000 soldiers, all well-equipped along with many supplies. They headed to Jiameng Pass at the border between Liu Zhang and Zhang Lu's territories. However, instead of engaging Zhang Lu, Liu Bei halted his advance and focused on building up connections and gaining influence around the area in preparation for his takeover of Yi Province. Since he was kind and virtuous, many among the masses soon joined him.(先主並軍三萬餘人，車甲器械資貨甚盛。是歲，璋還成都。先主北到葭萌，未即討魯，厚樹恩德，以收眾心。) Sanguozhi vol. 32. Among them was an eccentric man named Peng Yang, he quickly became friends with Pang Tong. With Pang Tong's and Fa Zheng's support, Peng Yang joined Liu Bei's staff. He revealed himself to be a highly talented military instructor and became even more favoured by Liu Bei.(統大善之，而法正宿自知羕，遂並致之先主。先主亦以為奇，數令羕宣傳軍事，指授諸將，奉使稱意，識遇日加。) Sanguozhi vol. 40.
Next year in 212, Liu Bei sent a letter to Liu Zhang where he told Zhang that he needed more troops to divert Cao Cao's attention away from the east and support Guan Yu against Yue Jin in Jing Province; he also mentioned that Zhang Lu was only looking to preserve his state and wouldn't engage in aggressive actions. Therefore, he requested another 10,000 soldiers and additional provisions to aid in the defense of Jing Province. Liu Zhang gave him 40% of the troops and half of the others he asked for. When he saw that Liu Zhang didn't fulfill his demands, Liu Bei rallied his men and asked them how Liu Zhang could expect them to risk their lives for him when he accumulated wealth while being picky about the distribution of their reward.(明年，曹公徵孫權，權呼先主自救。先主遣使告璋曰：「曹公徵吳，吳憂危急。孫氏與孤本為脣齒，又樂進在青泥與關羽相拒，今不往救羽，進必大克，轉侵州界，其憂有甚於魯。魯自守之賊，不足慮也。」乃從璋求萬兵及資（寶），欲以東行。璋但許兵四千，其餘皆給半。) Sanguozhi vol. 32. (〈《魏書》曰：備因激怒其眾曰：「吾為益州徵強敵，師徒勤瘁，不遑寧居；今積帑藏之財而吝於賞功，望士大夫為出死力戰，其可得乎！」〉) Wei Shu annotation in Sanguozhi vol. 32.
When Zhang Song heard that there were discussion about Liu Bei leaving to defend Jing province, he pressed Liu Bei and Fa Zheng to stay in Yi province. Soon, Zhang Su (張肅), Zhang Song's brother, discovered his brother's secret communications with Liu Bei, feared that he would become a victim if he failed, and reported the issue to Liu Zhang. Liu Zhang was furious and stunned when he heard that Zhang Song had been helping Liu Bei to plot against him; he executed Zhang Song and ordered his military officers guarding the passes to Chengdu to keep secret his knowledge of Liu Bei's intentions.(張松書與先主及法正曰：「今大事垂可立，如何釋此去乎！」松兄廣漢太守肅，懼禍逮己，白璋發其謀。於是璋收斬松，嫌隙始構矣。 璋敕關戍諸將文書勿複關通先主。) Sanguozhi vol. 32.
When Wei officials heard about the starting conflict between Liu Bei and Liu Zhang, there were discussions about who would overcome the other. Zhao Jian (趙戩) believed that Liu Bei didn't have the talent to accomplish such a task, highlighting his past failures as well as Yi province's natural defences making it easy to defend and difficult to conquer. However Fu Gan (傅幹) argued that: "Liu Bei is benevolent and tolerant and his men are willing to give their lives in his service. Zhuge Liang is a perspicacious administrator who quickly grasps the changing situations. He is honorable, talented in planning and work as his chancellor. Zhang Fei and Guan Yu are brave and also possess righteousness. Both of them are known as warriors who are a match for ten thousand men (萬人敵) and are his commanders. These three men are heroes. Knowing of Liu Bei's awareness along with those three heroes assisting him. How could he not succeed?"(傅子曰：初，劉備襲蜀，丞相掾趙戩曰：“劉備其不濟乎？拙於用兵，每戰則敗，奔亡不暇，何以圖人？蜀雖小區，險固四塞，獨守之國，難卒並也。”徵士傅幹曰：“劉備寬仁有度，能得人死力。諸葛亮達治知變，正而有謀，而為之相；張飛、關羽勇而有義，皆萬人之敵，而為之將：此三人者，皆人傑也。以備之略，三傑佐之，何為不濟也？”) Fu Zi annotation in Sanguozhi vol. 32.
Early Success (January or February 213–April or May 213) Liu Bei learned about what happened to Zhang Song from secret informers. Fa Zheng and Meng Da were already with his army and choose to defect to Liu Bei's side before Yang Huai () and Gao Pei (), Liu Zhang's subordinates guarding Baishui Pass (白水關), knew about Liu Bei's true intentions. Now, Liu Bei had no choice but to conquer Yi Province. Pang Tong outlined three plans for Liu Bei to choose from: The first was to advance swiftly to seize Chengdu, the capital of Yi Province, from Liu Zhang. The second was to take command of Liu Zhang's armies in the north and then move to capture Chengdu. The third one was to return to Baidicheng to await further action.(璋既還成都，先主當為璋北征漢中，統復說曰：「陰選精兵，晝夜兼道，徑襲成都；璋既不武，又素無預備，大軍卒至，一舉便定，此上計也。楊懷、高沛，璋之名將，各仗彊兵，據守關頭，聞數有牋諫璋，使發遣將軍還荊州。將軍未至，遣與相聞，說荊州有急，欲還救之，並使裝束，外作歸形；此二子既服將軍英名，又喜將軍之去，計必乘輕騎來見，將軍因此執之，進取其兵，乃向成都，此中計也。退還白帝，連引荊州，徐還圖之，此下計也。若沈吟不去，將致大因，不可久矣。」) Sanguozhi vol. 37.
Liu Bei chose the second option. He lured Yang Huai and Gao Pei into a trap and executed them under the pretense of behaving disrespectfully towards him.(先主大怒，召璋白水軍督楊懷，責以無禮，斬之。) Sanguozhi vol. 32. Wei Yan, who had just begun to serve under Liu Bei, was appointed as a bodyguard in his retinue; he made numerous achievements in several battles.(以部曲隨先主入蜀，數有戰功，) Sanguozhi vol. 40. When they learned of Liu Bei's attack, Zheng Du (鄭度) remarked that Liu Bei's army was isolated and consisted of only 10 000 soldiers, hence he suggested to Liu Zhang a scorched earth policy by forcing the civilians of Baxi (巴西) and Zitong (梓潼) commanderies to relocate elsewhere and destroy all the supply depots in the commanderies. Zheng Du reasoned that Liu Bei's army was low on supplies and composed of new recruits who may not be loyal to him. Following this strategy along with a solid defence into the fortress while refusing any engagement in open battles would force Liu Bei to retreat and allow Liu Zhang to launch a counterattack. Liu Bei felt greatly disturbed when he learned about the plan, but Fa Zheng reassured him that Liu Zhang would never follow this plan. Fa Zheng he was proven right as Liu Zhang told his subordinates: "I have heard of fighting the enemy to save the people; not of disrupting the people to avoid the enemy." Furthermore, he removed Zheng Du from office.(鄭度說璋曰：「左將軍縣軍襲我，兵不滿萬，士衆未附，野穀是資，軍無輜重。其計莫若盡驅巴西、梓潼民內涪水以西，其倉廩野穀一皆燒除，高壘深溝，靜以待之。彼至，請戰，勿許，乆無所資，不過百日，必將自走。走而擊之，則必禽耳。」先主聞而惡之，以問正。正曰：「終不能用，無可憂也。」璋果如正言，謂其羣下曰：「吾聞拒敵以安民，未聞動民以避敵也。」於是黜度，不用其計。) Sanguozhi vol. 37.
Finally, Liu Bei had Huang Zhong and Zhuo Ying (卓應) lead his soldiers against Liu Zhang.(乃使黃忠、卓膺勒兵向璋。) Sanguozhi vol. 32. During this campaign, Huang Zhong would show great martial skills and was always the first to break the ennemy's formations.(自葭萌受任，還攻劉璋，忠常先登陷陣，勇毅冠三軍。) Sanguozhi vol. 36. When Liu Bei entered the different passes; he took the commanders as hostage along with their family, wives and children. Then, he took command of their troops. Liu Bei led his army along with Huang Zhong and Zhuo Ying to attack Fu County (涪縣; present-day Mianyang, Sichuan) and occupied the city.(先主徑至關中，質諸將並士卒妻子，引兵與忠、膺等進到涪，據其城。) Sanguozhi vol. 32.
Following those success, Liu Bei organized a banquet where he expressed his great joy having conquered all the passes. He said to Pang Tong that today is an auspicious day. However Pang Tong answered that celebrating warfare isn't what a benevolent man should do. Liu Bei was angry at his response and told him that he should leave. Liu Bei came to regret his actions and asked for Pang Tong to rejoin him. Pang Tong then drank and eat as before, when Liu Bei asked him who was in the wrong previously, he answered both of them. Liu Bei greatly laughed and feasted as before.(先主然其中計，即斬懷、沛，還向成都，所過輒克。於涪大會，置酒作樂，。。。先主大笑，宴樂如初。) Sanguozhi vol. 37.