Conquest of Shu by Wei

The Conquest of Shu by Wei was a military campaign launched by the state of Cao Wei against its rival Shu Han in 263 during the Three Kingdoms period of Chinese history. The campaign culminated in the fall of Shu and the tripartite equilibrium maintained in China for over 40 years since the end of the Han Dynasty in 220. The conquest signified the beginning of a reunified China under the Jin Dynasty.

Background
At that time, three contending states were established after the collapse of the 400-year old Han Dynasty in 220. Among the three, Cao Wei in the north was the dominant military power in terms of economic resources, manpower, and geographic size, suppressing Shu Han in the southwest and Eastern Wu in the southeast. Noting this, Shu chancellor Zhuge Liang initiated an alliance between Shu and Wu to counter Wei's supremacy, and began a series of ill-fated attempts to capture the Wei capital from 228 until Zhuge's death in 234. Zhuge Liang's protege Jiang Wei had his own Northern Expeditions from 247 to 262. Jiang Wei's attempts were even more hurtful to Shu than those of Zhuge Liang, and were criticized by both contemporaries and later historians as wastes of men and resources. These campaigns strained the already disadvantaged Shu, while its incapable emperor Liu Shan indulged in pleasures and neglected state affairs.

Meanwhile in Wei, the Sima clan, through years of political maneuvering, had ousted the imperial family from power and reduced the roles of the Wei emperors to mere figureheads. The Wei regent and de facto ruler, Sima Zhao, believed that a successful military campaign to reunify China would bolster his prestige and convince the imperial court that the Mandate of Heaven had fallen on the Sima family, which would minimize the opposition for a formal succession. Disturbed by Jiang Wei's constant harassments on the Wei border and aware of Shu's internal decay, Sima Zhao decided that the conquest of Shu would be a vital step in unifying All Under Heaven.

The decision to conquer Shu
In 262, Sima Zhao announced his intention to conquer Shu. Most subjects in the Wei imperial court were against such a campaign, including general Deng Ai, who was at the forefront of fighting Shu in the past. Against the majority, Zhong Hui strongly supported the campaign, and was the most influential factor that turned the opinion in the imperial court to yield. Sima Zhao consequently assigned his personal secretary, Registrar Shi Cuan (师纂), as a major in Deng Ai's army to "convince" him, which Shi Cuan successfully did and turned Deng's opposition to support.

Wei's decision to launch a campaign against Shu first was the result of careful strategic analysis. Its other rival state, Wu, enjoyed the natural barrier, the Yangtze River, and a strong navy with over 5,000 ships. Wei's lack of a strong navy meant that it must take its time to build one and train the sailors first if it was to attack Wu. If Shu was attacked, forces of Wei would be marching on land, avoiding the problem it would face in the campaign against Wu. Also, with Shu gone, Wei would concentrate its forces on Wu without worrying being attacked from the west. Shu was the smallest among the Three Kingdoms, with only 100,000-men strong force, less than half of the 230,000 troops Wu had. Despite its small size, Shu had been taking a very aggressive posture by constantly attacking Wei, which proved to be a major mistake, as Sima Zhao used it as a reason to force the Wei court into accepting his plan.

Strategy of Wei
Sima Zhao made a detailed plan to conquer Shu by appointing Zhong Hui as the commander of the expedition force, while in a move to disguise his true objective, general Tang Zi was placed in charge of building a strong navy for the preparation of campaign against Wu. In reality, more than 200,000 troops would be grouped in Guanzhong under Zhong Hui's command, for the true objective: the campaign against Shu.

Wei would attack Shu in three fronts, with the eastern front as the main thrust, initially attacking Hanzhong from Xie Valley (斜谷; south of present-day Mei County, Shaanxi), Luo Valley (駱谷), and Ziwu Valley (子午谷, south of present-day Xi'an, Shaanxi). After that, the three forces at the eastern front would join forces and continue the push toward the heart of Shu. The western force would engage Jiang Wei at Tazhong (沓中; northwest of present-day Zhugqu County, Gansu) from four directions and then join the main force. The central front would attack Wuje Bridge (武街橋; northwest of present-day Cheng County, Gansu) from Mount Qi (祁山; in present-day Li County, Gansu), cutting off Jiang Wei's retreat route, preventing his army from reinforcing the passes along the attack route.

Strategy of Shu
Previously, Wei Yan invented a defense mechanism to hinder and repel invading forces by setting up "covering camps" on the outskirt and exits of trails leading to Hanzhong. Even after Wei Yan's death, Shu had been following his arrangement, and succeeded in driving out Wei forces everytime. However, Jiang Wei argued Wei Yan's design "could only repel the enemy but not reaping big profit." To anticipate a Wei attack, Jiang Wei proposed to abandon the camps set up by Wei Yan and vacate all the passes in the Qinling Mountains so the Wei forces would go deep into the Hanzhong plain, where the worn-out expedition force would be vulnerable to a Shu counterattack upon retreat. Jiang Wei assured the Shu emperor Liu Shan that was how to achieve a decisive victory previously unattained when they had just defended along the Qinling Mountains. This strategy, however, was erred in that Wei had mobilized its forces in a way Jiang Wei had never imagined, as the later course of events would point out.

On the eve of the Wei invasion, Jiang Wei had received intelligence that Wei would launch a major offensive and wrote to the Shu imperial court in Chengdu, urging Liu Shan to send Liao Hua to Yang'an Pass (陽安關) and Zhang Yi to Yinping (陰平). Liu Shan, however, trusted his eunuch Huang Hao, who believed in witchcraft. Huang Hao believed that Wei would not dare to attack Shu and such belief was "confirmed" by a witch doctor when asked. As a result, Jiang Wei's letter was kept a secret to avoid "unnecessary panic", and no one else knew about it. However, on second thought, Liu Shan sent out Liao Hua and Zhang Yi before the engagement started.

Prelude
In the autumn of 263, an order to invade Shu was formally issued by the Wei imperial court. Xu Yi (許儀), son of Xu Chu, was in charge of constructing roads for the Wei army. However, the road was poorly built and one of the bridges nearly broke when Zhong Hui was crossing. As a result, Xu Yi was executed on Zhong Hui's order, and everyone was shocked. In doing so, Zhong Hui established his authority and the road was built far more efficiently.

When Wei mobilized its troops in September 263, Jiang Wei's plan worked -- only for its first half that Wei forces advanced unopposed until they reached the fortresses of Han (漢; located in present-day Mian County, Shaanxi) and Yue (樂; located in present-day Chenggu County, Shaanxi), which served as a bait to wear the enemy out.

In addition to redeploying its troops toward Han and Yue fortresses, Shu also requested aid from Wu, which responded rapidly by attacking Wei in the east in the hope of forcing Wei to switch its focus and abandon its campaign against Shu. The Wu General-in-Chief, Ding Feng, led the majority of the Wu army to attack Shouchun, while Wu generals Liu Ping (留平) and Shi Ji (施績) attacked Nan Commandery (南郡), while Ding Feng (younger brother of the earlier mentioned Ding Feng) and Sun Yi (孫異) attacked Mianzhong (沔中). However, as Wei was prepared, such attacks were rather ineffective and did not alter the course of the war.

Zhong Hui's advance
The eastern front of the campaign, where the main thrust was, did not progress as Jiang Wei expected. When Zhong Hui reached the two fortresses of Han (guarded by Jiang Bin (蔣斌)) and Yue (defended by Wang Han (王含)), he did not fall into the trap to be worn out. Instead, Zhong Hui simply split out two detachments to besiege the two fortresses, and speedily continued to press on. Wei's General of the Vanguard, Li Fu (李輔) was assigned 10,000 troops to besiege Yue, while General Who Protects the Army Xun Kai (荀愷) was assigned another 10,000 troops to besiege Han. Both Shu commanders proved to be incapable as to follow Jiang Wei's dull orders to just defend the city and let the main force of the enemy go.

As mentioned earlier, Shu emperor Liu Shan had sent Liao Hua to Tazhong. That was against Jiang Wei's view to reinforce Yinping (陰平), because Liu Shan's first priority was to get Jiang Wei out from possible annihilation. Jiang Wei's force, despite suffered some defeats from Wei generals Wang Qi (王頎) and Yang Qu (楊趨), was able to avoid total destruction by his own ingenuity. When Jiang Wei was heading back, his force was once in danger of being obliterated when the pursuing Yang Qu caught up with him while another Wei force under Zhuge Xu (諸葛緒) blocked his way at Yinping bridge. To trick Zhuge Xu into opening a passage, Jiang Wei led his men from Konghan Valley (孔函谷; southwest of present-day Wudu District, Gansu) to the rear of Zhuge Xu's force, appearing to be cutting off the latter's retreat route. Fearing this may happen, Zhuge Xu ordered his force to retreat 15 km and Jiang Wei immediately turned back and crossed the bridge. Once Zhuge Xu learned that he was tricked, Jiang Wei's force was long gone and it was impossible to catch up with his force. However, when Jiang Wei safely retreated, he only perceived the imminent attack from Zhong Hui, and even took the local troops at Yinping toward Guancheng, further weakening the defense at Yinping. This blunder was instrumental in Deng Ai's later operation, which brought the downfall of Shu.

Within weeks, Zhong Hui swiftly arrived at Yang'an. There, Dong Jue and Zhang Yi put up some resistance, but Shu's inferior military mobilization and human resources assisted Zhong in achieving a quick victory over them. Despite gaining large portions of land, the length of Zhong Hui's supply line grew longer as his force was deeper into the enemy territory. If a logistic problem arose, Zhong Hui might be forced to retreat, losing all the territory newly gained. Hence, Zhong Hui sent his vanguard, Hu Lie (胡烈), to take Guancheng, where Shu forces stockpiled their food supply. Earlier on, the Shu commander of Wuxing, Jiang Shu, had born a furtive grudge against Shu's management when he was demoted and put under Fu Qian. Once Hu Lie arrived at Guankou, Fu Qian and Jiang Shu disagreed in the manner they should defend. Jiang Shu, using the pretext of engaging the Wei force outside the gates, led his original subordinates out of the pass and surrendered to Hu Lie. Furthermore, Jiang Shu opened the gates and let the enemy in when Fu Qian laid his guard down. Fu Qian fiercely resisted the enemy but was killed and Zhong Hui acquired the bulk of supplies stored inside Guancheng. Thus, Zhong Hui's supply problem was temporarily solved. At the time Zhong Hui beached Guankou, Jiang Wei was still lingering on his way to the battlefield. When he knew Guancheng was taken, Jiang Wei spontaneously changed his destination to Jiange (劍閣; present-day Jiange County, Sichuan), where he hoped the great pass could resist the enemies.

Taking a break from the battlefield, Zhong Hui spent some time to visit Zhuge Liang's tomb and personally wrote to Jiang Bin, who was still busy guarding Han fortress, telling the latter that he had already paid his respect to Zhuge Liang at his tomb. Zhong Hui wanted to show he could win this war with ease, so he told Jiang Bin he wanted to pay his respect to Jiang Wan, Jiang Bin's late father, and asked Jiang Bin where Jiang Wan's tomb was. Refusing to concede, Jiang Bin replied politely that his father died in Fu County (涪縣), and Zhong Hui could pay his respect to Jiang Wan on his way west. Fu County was almost 500 km to the west of Yang'an pass, deep in the heart of Shu, and Jiang Bin's reply was a show of confidence that Wei army could not pass Jiange. Indeed, Jiang Bin successfully held out against Zhong Hui and it was only after the surrender of Liu Shan did he eventually surrender. Despite this minor setback, the glorious achievement of taking Hanzhong was enough for Sima Zhao to finally accept the title of the "Duke of Jin" (晉公) in Luoyang on October 22, 263, after rejecting the previous six offers from the Wei imperial court. However, Zhong Hui's continuous push toward Chengdu was checked at the Jiange stronghold where the defeated Shu forces regrouped, thus a stalemate was reached.

Deng Ai's tactic


Earlier, when Deng Ai reached Yinping, he asked Zhuge Xu to join him to bypass Jiange by directly attacking Chengdu via Jiangyou. Deng Ai's plan was rejected by Zhuge Xu as being too ambitious; he preferred a more cautious approach. Stating his job was to destroy the force led by Jiang Wei, Zhuge Xu led his men eastward to join Zhong Hui. However, Zhong Hui wanted to merge the troops under the faint-hearted Zhuge Xu, so he secretly reported to the Wei imperial court about Zhuge Xu's cowardliness to cooperate with Deng Ai, and as a result, Zhuge Xu was tied up in a cage and sent back to the Wei capital Luoyang, while all of his previous troops were seized by Zhong Hui. However, the strengthened numerical superiority proved to be no help at all when against the geographical advantage held by the defenders: Mount Dajian (大劍山) and Mount Xiaojian (小劍山) at Jiange enabled Jiang Wei's 50,000 strong force to hold out against Zhong Hui's 130,000+ troops, and more importantly, the supply of such a huge army was running low and Sima Zhao once wanted to give order to retreat. Feeling Deng Ai's strategy had no chance of any success, Zhong Hui agreed to let Deng Ai venture towards Jiangyou, and even assigned his own men under Tian Zhang to join Deng Ai's operation.

The route Deng Ai chose was nearly impassible and all the enemy had to do was to starve his force by staying behind the protection of the city walls. Deng Ai's force would even be annihilated much quicker if the enemy ventured out to attack them, for that Deng Ai's force had to travel over 350 km of impassible terrain without any roads, thus leaving little or no horses and supplies. The exhausted troops would be an easy target. However, there were advantages: since the route Deng Ai chose was considered impassible, Shu did not deploy any forces along the way. Furthermore, after the stalemate was reached at Jiange and Zhong Hui's force begun to have supply problems, Shu was confident that the Wei forces would retreat. As a result, no troops were deployed to strengthen the defense of the Shu capital Chengdu, and general Huo Yi's request to lead his force to reinforce the capital was denied, as with all similar requests. To boost his men's confidence and morale, Deng Ai personally led the way.

After Deng Ai's force reached Jiangyou after safely made it through its 350 km journey in October 263, the Administrator of Jiangyou, Ma Miao, was so surprised by the sudden appearance of Deng Ai's force hundreds of miles behind the frontline and deep in the heartland of Shu, that he surrendered without a fight. This provided much needed rest and supply Deng Ai's force desperately needed and after getting both, Deng Ai led his force continued on toward Chengdu. The sudden appearance of Deng Ai's force so close to the capital and the fall of Jiangyou shocked Liu Shan. Zhuge Zhan, son of Zhuge Liang, had led an army in Fu County at the time, but he was too frightened to engage the enemy, when Huang Chong urged Zhuge Zhan to secure advantageous terrain before Deng Ai would get to a flat plain, Zhuge Zhan simply did not know what to do. When Huang Chong cried, Zhuge Zhan appeased the former by sending out his vanguard to do battle, but was promptly crushed. In fear, Zhuge Zhan fled the battlefield and asked Liu Shan for help. Liu Shan sent the last available men to the heavily fortified Mianzhu Pass (綿竹關), where Zhuge Zhan calmed down and prepared to defend.

When Deng Ai tailed Zhuge Zhan to Mianzhu Pass, he gave a last chance to the latter and promised Zhuge Zhan that he would recommend him to be the "King of Langye". However, Zhuge Zhan executed Deng Ai's messenger, moved out from the fortress, and supposedly arranged the Eight Trigrams Formation improved by Zhuge Liang. Deng Ai initially attacked Zhuge Zhan's formation in a pincer movement, with his son Deng Zhong at the right and Shi Cuan at the left. However, the initial attack was beaten back and the angry Deng Ai ordered an all out attack on the enemy, and threatened to behead both commanders of his if the second attack failed. The second attack was successful, completely defeating the enemy. Shu commanders including Zhuge Zhan, his son Zhuge Shang, Imperial Secretaries Huang Chong and Zhang Zun, and Right Commander of the Feathered Forest Imperial Guards Li Qiu (李球) were all killed in action. Zhuge Zhan's defeat at Mianzhu Pass and the subsequent fall of the city meant that the gateway to Chengdu was wide open, and Deng Ai's force marched on toward Shu's capital Chengdu after taking Luo County (雒縣; north of present-day Guanghan, Sichuan) on its way.

The fall of Shu
While other forces of Shu such as those led by Jiang Wei were hundreds of miles away, Shu was unable to gather anymore forces to defend its capital, and the subjects in the imperial court were divided on what to do in their panic. Some had suggested to flee southward to the Nanzhong (border region of present-day southern Sichuan, Yunnan and Guizhou) region while others suggested to flee to Eastern Wu, but the future for both were bleak and uncertain at the best. One of Liu Shan's sons, Prince of Beidi Liu Chen, advocated resistance, suggesting that they still have a chance given that Deng Ai's forces had exhausted themselves after the perilous journey. However, Liu Shan disregarded this advice, and Liu Chen, in despair, killed his wife and children before committing suicide in the ancestral temple. Finally, Liu Shan accepted Qiao Zhou's suggestion to surrender and sent Zhang Shao (張紹) Zhang Fei's second son, and Deng Liang (鄧良), Deng Zhi's son, to Luo County to inform Deng Ai that he would surrender, carrying the Imperial Seal of Shu. In November 263, Liu Shan had both his hands tied behind his back, a casket behind him, with more than five dozen subjects in waiting, formally surrendered to Deng Ai outside Chengdu, marking the end of Shu. Deng Ai accepted the surrender by untying Liu Shan and burning the casket.

Jiang Wei, meanwhile, was still holding off Zhong Hui at Jiange. He first learned the news of the disastrous defeat of Zhuge Zhan but failed to know what exactly happened to the emperor Liu Shan. He decided to withdraw from Jiange, to avoid being attacked by the enemy from both the front and rear, and successfully lost Zhong Hui's force chasing him once reaching Bazhong. Once he reached Qi County (郪縣; present-day Shehong County, Sichuan), Jiang Wei received Liu Shan's imperial decree ordering him to surrender, so he obeyed by surrendering to Zhong Hui at Fu County.

The final military engagement of Shu was not against Wei but against Wu on the eastern border of Shu. Wu general Sheng Xian, using the pretext of assistance and support, led his army toward the Shu garrison at Yong'an in hopes of enhancing the Wu defenses along the Yangtze River by capturing the region. The Administrator of Badong, Luo Xian, deciding that their Wu allies could not be trusted, put up a staunch defense against Wu and submitted to Wei, honouring Liu Shan's last decree as an emperor. Wu forces under Lu Kang besieged the garrison for six months before they had to retreat when Hu Lie of Wei threatened the line of communication of Wu.

Many refugees such as nobles and troops fled west to Sasanian Persia when Shu fell.

Wei forces
The Wei offensive would be split into three prongs, each with a specific mission and answerable to Sima Zhao. The three prong would act independently, with Zhong Hui and Deng Ai having the staff of authority to intercede when necessary. This arrangement meant that the three commanders could largely kept watch on each other, preventing the possibility of one commander taking full control of the expedition force and rebel.


 * Eastern flank
 * Director of Retainers (司隸校尉) Zhong Hui, the strongest supporter of Sima Zhao's decision to launch the campaign, was rewarded with the rank of General Who Stabilizes the West (鎮西將軍), and was named as the Area Commander (都督) of Guanzhong. Zhong Hui was in charge of the eastern front, the main thrust, commanding over 100,000 troops attacking Hanzhong.
 * General Who Stabilizes the West (鎮西將軍) Du Yu
 * General of the Vanguard (前將軍) Li Fu (李輔)
 * General Who Protects the Army (護軍將軍) Xun Kai (荀愷), great-grandson of Xun Yu and maternal grandson of Sima Yi
 * General Who Protects the Army (護軍將軍) Hu Lie (胡烈) was named as the vanguard of the eastern front
 * Administrator of Weixing (魏興太守) Liu Qin (劉欽) as the deputy vanguard of the eastern front


 * Western flank
 * General who Subdues the West (征西將軍) Deng Ai, who was already an Area Commander (都督) of Longyou, was given 30,000 troops to attack Jiang Wei at Tazhong from the western front. This force was to split in two directions, with Deng Ai himself attacking Gansong (甘松, south of present-day Têwo County, Gansu) from Didao (狄道, present-day Lintao County, Gansu), while three subordinates of his would attack Tazhong directly.
 * Administrator of Tianshui (天水太守) Wang Qi (王頎) would attack Jiang Wei at Tazhong from the east
 * Administrator of Longxi (隴西太守) Qian Hong would attack Jiang Wei at Tazhong from the north
 * Administrator of Jincheng (金城太守) Yang Qu (楊趨) would attack Jiang Wei at Tazhong from the west
 * Deng Ai's son, Deng Zhong, the Marquis of Huitang (惠唐亭侯), was assigned as Deng Ai's vanguard
 * Registrar (主簿) Shi Cuan was assigned as a major (司馬) in Deng Ai's army.


 * Central flank
 * The Inspector of Yong Province (雍州刺史) Zhuge Xu (諸葛緒) was given 30,000 troops, and would block Wujie Bridge (武街橋) in attempt to cut off Jiang Wei's retreating route.

Shu forces
Of the 40,000 officers of Shu, listed are some commanders who participated in the campaign.


 * General-in-Chief (大將軍) Jiang Wei
 * General of Chariots and Cavalry on the Right (右車騎將軍) Liao Hua
 * General of Chariots and Cavalry on the Left (左車騎將軍) Zhang Yi
 * Senior General Who Assists the Nation (輔國大將軍) Dong Jue
 * Guanzhong Area Commander (關中都督) Fu Qian
 * General Jiang Shu, served as Fu Qian's deputy
 * General Who Protects the Army (護軍將軍) Jiang Bin (蔣斌)
 * Army Inspector (監軍) Wang Han (王含)
 * Administrator of Jiangyou (江油太守) Ma Miao
 * General Who Protects the Army (護軍將軍) Zhuge Zhan
 * Zhuge Shang, Zhuge Zhan's son, served as commander of his father's vanguard
 * Imperial Secretary (尚書) Huang Chong
 * Imperial Secretary (尚書) Zhang Zun
 * Right Commander of the Feathered Forest Imperial Guards (羽林右部督) Li Qiu (李球)

Modern references

 * Mie Shu Ji (滅蜀記; literally: The Tale of the Destruction of Shu) is a 2008 novel by Li Bo (李柏) that dramatises the events leading to the fall of Shu, with Jiang Wei, Deng Ai and Zhong Hui as the central characters.


 * The Conquest of Shu by Wei was featured as the final stage of the Jin Dynasty's campaign in the seventh installment of Koei's Dynasty Warriors video game series.