Conquest of Wu by Jin

The conquest of Wu by Jin was a military campaign launched by the Jin Dynasty against the state of Eastern Wu in 280 towards the end of the Three Kingdoms period of Chinese history. The campaign concluded with the fall of Wu and the reunification of China under the Jin Dynasty.

Background
As early as 262, Cao Wei regent Sima Zhao planned the first outline for the conquest of Wei's rival states, Eastern Wu and Shu Han, by eliminating Shu first, then take on Wu three years later. However, the conquest of Shu in the following year severely strained Wei's resources and Wei desperately needed time to recover. Compounding the problem, Wei lacked an adequate naval force required for the campaign on Wu. Sima Zhao therefore postponed the planned conquest of Wu and started to consolidate power in Wei first. In 265, Sima Zhao died and was succeeded by his son, Sima Yan. In the same year, Sima Yan forced the last Wei emperor, Cao Huan, to abdicate, and proclaimed himself Emperor of the Jin Dynasty. By then, only Wu was left of the Three Kingdoms.

In comparison with Wei and the subsequent Jin Dynasty, Wu experienced greater problems of its own: the succession from the third Wu emperor, Sun Xiu, was marred with bloodshed and internal conflict. Sun Xiu's successor, Sun Hao, was a tyrant who made little effort to prepare for the imminent invasion by the Jin Dynasty. Sun Hao's rule was more harsh as compared to the later part of the reign of Sun Quan, Wu's founding emperor. This caused a continuous wave of peasant uprisings and military mutinies, which mainly took place in present-day Zhejiang and Guangdong. Not only did Sun Hao refuse to accept advice to strengthen Wu's defenses and reduce the burden on its people, he also executed around four dozen high-ranking officials who provided good counsel on governance. As a result, the Wu imperial court had already lost the popular support of the people, and many regional commanders stationed at the border defected to the Jin Dynasty.

Prelude
To stabilize the newly conquered state of Shu, as well as showing benevolence toward the people of Wu so that they would defect or surrender to the Jin Dynasty, the surrendered Shu emperor Liu Shan was granted the rank of "Duke of Anle", and over fifty former subjects of Shu were awarded the titles of marquises. Zhuge Liang's grandson, Zhuge Jing (諸葛京), also received important appointments in the Jin imperial court. At the same time, Jin sent envoys to Wu to cease hostilities between the two states, in order to buy time for making preparations. Wu's emperor Sun Hao, in turn, viewed such actions as a sign of weakness of Jin, and further let down his guard.

Jin preparations
Jin preparation for the conquest of Wu begun in 269, when three places were selected as bases to launch the attack. New assignments were given as follows:


 * Imperial Secretary Yang Hu was appointed as the viceroy of Jing Province and stationed at Xiangyang.
 * Senior General Who Conquers the East Wei Guan was appointed as the viceroy of Qing Province and stationed at Linzi (臨菑; northeast of present-day Zibo, Shandong).
 * Prince of Langye and Senior General Who Stabilizes the East Sima Zhou was appointed as the viceroy of Xu Province and stationed at Xiapi (下邳; northwest of present-day Suining County, Jiangsu).

On Yang Hu's recommendation, Emperor Wu of Jin (Sima Yan) appointed Wang Jun as the viceroy of Yi Province, (益州; covering the Sichuan Basin) in 272, and soon after, on Du Yu's advice, Emperor Wu promoted Wang Jun to the rank of General of the Uplifting Dragon. Wang Jun was put in charge of building a strong navy for the conquest of Wu. An ambitious general who was already turned 70, Wang Jun was eager to establish fame by the conquest of Wu, and while he was only an Administrator of Yi Province, he already begun the process. The new ranks sped up the process tremendously by enabling Wang Jun to draft much more men: in comparison to the 500 to 600 workers previously available, every commandery within his control must provide him with 10,000 men. As a result, the remaining work of the naval construction project was completed in a year.

To make up for their lack of experience of naval warfare in comparison to Wu's navy, Wang Jun built many large ships with ram bows. The largest ship was in excess of 170 metres and could carry around 2,000 troops on board. The fortifications on these ships were three stories tall and was claimed to be the largest at the time. It took Wang Jun a total of seven years to build the navy he needed to conquer Wu and the only thing left to do was to train his soldiers and sailors.

In October 276, the preparation was roughly completed and Yang Hu suggested to the emperor to launch the attack. Yang Hu's suggestion was initially accepted but then delayed due to Grand Commandant Jia Chong's opposition, because Xianbei leaders had rebelled in northwestern China. In July 277, additional assignments were given in order to prepare for the campaign against Wu:

After Yang Hu's death, Du Yu succeeded him and was awarded the rank of Senior General Who Conquers the South, taking charge of military affairs in Jing Province from November 278.
 * General who Establishes Might Wang Hun (王渾) was put in charge of military affairs of Yang Province
 * Senior General Who Stabilizes the South Sima Liang was put in charge of military affairs of Yu Province
 * General of the Left Hu Fen (胡奮) was put in charge of military affairs along the northern shore of the Yangtze River

Wu preparations
In comparison to the active preparation of its adversary, what the Wu emperor Sun Hao did was nearly nothing. During Wang Jun's naval construction, the leftover wooden pieces flowed downstream and were picked up by the Administrator of Jianping (建平, present-day Zigui County, Hubei), Wu Yan (吾彥). Wu Yan sent the wooden pieces to Sun Hao as evidence of the imminent attack and asked for reinforcements, but the request was ignored, as with similar suggestions from Lu Kang (son of Lu Xun) and others.

After Lu Kang's death, his military command was split among his five sons as follows:
 * Eldest son Lu Yan (陸晏) was appointed as the commander-in-chief of the land force
 * Second son Lu Jing was appointed as the commander-in-chief of the navy
 * Third son Lu Xuan (陸玄) was appointed as the deputy commander-in-chief of the land force
 * Fourth son Lu Ji was appointed as the deputy commander-in-chief of the navy
 * Fifth son Lu Yun (陸雲) was appointed as the commander of the local garrison

The division greatly weakened Wu's defenses and three of Lu Kang's sons were killed in the battles when Jin conquered Wu.

Strategic planning
In 279, Wang Jun thought that it was time to launch the decisive attack on Wu, and as with similar petitions submitted previously, it was strongly objected by nearly all subjects in the Jin imperial court, with the exception of two, General Who Conquers the South Du Yu and Imperial Secretary Zhang Hua, who strongly supported Wang Jun's idea. Furthermore, the two managed to convince Emperor Wu of Jin to agree with them, and the strategy of Jin was basically the one planned by Yang Hu when he was alive. 200,000 troops out of the 500,000 strong regular army of Jin were deployed for the campaign, and by this time, the Jin navy was also at least equal if not stronger than Wu's.

Jin strategy
The Jin army did not enjoy numerical superiority because it faced the entire Wu force of 230,000 and over 5,000 ships that defended the state. However, the morale of Jin was much higher than Wu. Furthermore, the Wu forces was scattered along the several thousand miles long border, and the attacking Jin armies could concentrate their forces to attack the isolated pockets of Wu resistance. Based on this principle, Jin would attack Wu along the Yangtze River in five routes to support the main attack force led by Wang Jun from Sichuan, going downstream along the Yangtze.

Wang Hun (王渾) and Sima Zhou were tasked to tie down the main force of Wu, preventing it from reinforcing the upstream Yangtze River by threatening Wu's capital, Jianye (present-day Nanjing, Jiangsu). Wang Rong, Du Yu and Hu Fen (胡奮) were tasked to take all strongholds of Wu located to the west of Xiakou (夏口; present-day Wuchang District, Hubei) to coordinate with the 70,000 strong main force led by Wang Jun. After the attacking forces had joined together, they would push toward east along the Yangtze River and the capture of Jianye would be the responsibility of Wang Hun, Sima Zhou and Wang Jun. To better coordinate the attack, Emperor Wu of Jin ordered that Wang Jun would be under Du Yu's command after reaching Jianping, and after reaching Jianye, he would be under Wang Hun's command.

Wu strategy
Since the Wu emperor Sun Hao did not believe that the Jin was capable of taking Wu and the overconfidence in the Yangtze River as the natural defensive barrier, barely anything was done to prepare for the incoming campaign. However, Wu did reinforce its defense by deploying iron awls linked together by iron chains in the Three Gorges to prevent ships from passing, but Sun Hao and his followers were so overconfident about this additional measure that not a single soldier was deployed to guard the region.

Battles at the upstream of the Yangtze River
Wang Jun's navy began its downstream Yangtze River attack in December 279 after being joined by his deputy, Tang Bin (唐彬) in charge of Badong commandery (巴東, present-day Fengjie County, Chongqing). The combined force totaled 70,000. A month later, in January 280, Du Yu begun his attack on Jiangling from Xiangyang and sent three of his advisors, Fan Xian (樊顯), Yin Lin (尹林), Deng Gui (鄧圭), along with Administrator of Xiangyang, Zhou Qi (周奇), westward along the Yangtze River to join Wang Jun, attacking the strongholds of Wu between them from both the east and the west. By February 280, Wang Jun's army had taken Danyang (丹楊, east of present-day Zigui County, Hubei) from Wu, and captured its Supervisor Sheng Ji (盛紀).

The Jin fleet under Wang Jun's command continued on after taking Danyang and upon reaching Xiling Gorge, they had met obstacles set up by Wu, the iron awls linked together by iron chains in water. However, Wang Jun had already captured most of Wu's agents, as well as many prisoners-of-war, and based the information obtained from the captives, the Jin forces already had a detailed knowledge of Wu's defenses, knowing exactly where the weakest spots were and where to attack. The Jin navy deployed dozens of rafts ahead of the fleet and when the iron awls struck the rafts, they were stuck. The rafts were full of dummies soaked in oil which were lit, causing the iron chains and awls to melt. After several hours, those man-made obstacles were completely cleared and the Jin fleet continued advancing.

By February 3, 280, Jin forces had taken Xiling (西陵; northwest of present-day Yichang, Hubei), and two days later, Jingmen and Yidao (夷道; present-day Yidu, Hubei) also fell under Jin control. All major Wu commanders, including Liu Xian (留憲), Cheng Ju (成據), Yu Zhong (虞忠), and Lu Yan (陸晏) were captured and then executed. The victorious Jin fleet continued its offensive against Lexiang (樂鄉; northeast of present-day Songzi, Hubei), defeating the local Wu forces who ventured out of the protection of city walls in an attempt to stop the Jin assault.

In the mean time, Du Yu had sent his subordinate Zhou Zhi to cross the Yangtze River with 800 horsemen at night to plant many flags in Mount Ba (巴山; southwest of present-day Songzi, Hubei), appearing to be a much larger force, while laying ambush just outside Lexiang. As the local Wu garrison went out earlier to engage Wang Jun's force retreated back to the city after their defeat, Zhou Zhi and his men were able to sneak into the city and capture it. The Commander of Lexiang, Sun Xin (孫歆), was captured by Zhou Zhi and sent to Du Yu. Wang Jun, in his report to the Jin imperial court, claimed that Sun Xin was killed in action. In fact, it was Wu's naval commander-in-chief, Lu Jing, who was killed when Lexiang fell to the Jin forces. Du Yu's army subsequently conquered Jiangling and killed its Commander Wu Yan (伍延).

Redeployment of Jin forces
On February 28, 280, Emperor Wu of Jin strengthened the main force under Wang Jun's command by redeploying troops under other commanders:


 * Du Yu to attack southward to take Lingling, (零陵; present-day Yongzhou, Hunan), Guiyang (桂陽; present-day Chen County 郴縣, Hunan), and Hengyang (衡陽; west of present-day Xiangtan, Hunan), and 10,000 troops under Du Yu's command would be reassigned to Wang Jun, and another 7,000 troops under Du Yu's command would be reassigned to Wang Jun's deputy Tang Bin (唐彬).


 * Hu Fen (胡奮) would take Xiakou (夏口; present-day Wuchang District, Hubei) together with Wang Jun's force, and after the city was taken, 7,000 troops under Hu Fen's command would be reassigned to Wang Jun.


 * Wang Rong would join forces with Wang Jun to take Wuchang (武昌; present-day Ezhou, Hubei), and after the city was taken, 6,000 troops under Wang Rong's command would be reassigned to Wang Jun's deputy Tang Bin.


 * After taking Baqiu (巴丘; present-day Yueyang, Hunan), Wang Jun's force would join forces with other commanders to take other cities as mentioned above, and then continue on toward Jianye, the capital of Eastern Wu.

Following Emperor Wu's orders, Wang Jun continued his offensive and Wu general Meng Tai (孟泰) surrendered with his forces guarding Qichun and Zhu (邾; present day Huanggang, Hubei). The next target was also captured without much fight: after Wang Rong's force led by Luo Shang (羅尚) and Liu Qiao (劉喬) joined Wang Jun and begun their offensive, Wu's Administrator of Wuchang, Liu Lang (劉朗), lost his will to resist and surrendered without a fight. With the exception of Jianping, which was defended by Wu Yan (吾彦), the Administrator of Jianping, all other territories of Wu on the upper Yangtze River had fallen under the Jin Dynasty's control.

By this time, Grand Commandant Jia Chong, the Jin commander-in-chief of the campaign who had opposed the campaign from the start, had found the opportunity to suggest a conclusion of the campaign. Jia Chong claimed that it was good to withdraw after the continuous victories because if the war continues, it would exhaust the resources of the state and troops remain the south would suffer from epidemics. However, the war progressed much faster and better than Jia Chong had predicted and his suggestion was ignored.

Battles midstream and downstream of the Yangtze River
At the midstream and downstream of the Yangtze River, starting in January 280, Wang Hun (王渾) conquered Wu's territories of Xunyang (尋陽; southwest of present-day Huangmei County, Hubei), Gaowang (高望; southwest of present-day Pu County 浦縣), and Laixiang (賴鄉), capturing Wu general Zhou Xing (周興). Sima Zhou took Tuzhong (涂中), sending his subordinate, Liu Hong (劉弘), to solidify the newly captured territory on the northern shore of the Yangtze River. Meanwhile, Sima Zhou sent Wang Heng (王恆) to cross the Yangtze River to continue attacking Wu. Wang Heng's army captured Wu general Cai Ji (蔡機) and killed more than 60,000 Wu troops in the battle.

Surprised with the news of attack, Sun Hao ordered Zhang Ti, Zhuge Jing (諸葛靓), Shen Ying (沈瑩) and Sun Zhen (孫震) to lead a 30,000 strong army to engage the enemy. Zhang Ti decided the only chance for Wu was to immediate venture out to stop the enemy before the morale collapse, and if the enemy's advance could be beaten back or at least checked, his force would join the Wu forces in the upstream Yangtze River to strengthen their position. In March 280, Zhang Ti led his force across the Yangtze and besieged Wang Hun's subordinate Zhang Qiao (張喬). Zhang Qiao only had 7,000 troops and surrendered. Zhuge Jing suspected that the surrender was a trick and asked Zhang Ti to execute Zhang Qiao, but Zhang Ti refused, and instead, accepted Zhang Qiao's surrender. As a precaution measure, Zhang Ti did order Zhang Qiao to remain by his side so that Zhang Qiao would not have the chance to escape back to Jin.

As the Wu army continued on, they encountered Jin forces led by Zhang Han (張翰) and Zhou Jun (周濬). Shen Ying personally led 5,000 crack troops from Danyang to charge into the Jin army's formation thrice, but was beaten back with heavy losses. The defeat of the elite force seriously demoralized the rest of the Wu soldiers, and the result was a disorganized retreat. Seizing on the opportunity, Jin generals Xue Sheng (薛勝) and Jiang Ban (蔣班) launched a surprise counterattack, defeating the Wu forces and killing over 5,800 enemy troops. As the surviving Wu forces fled from the battlefield, the surrendered Zhang Qiao attacked the fleeing Wu soldiers from the opposite direction at Banqiao (版橋), inflicting a further 2,000 fatalities on the already defeated Wu army. Zhang Ti, Shen Ying, and Sun Zhen were all killed in the decisive battle that shocked Wu. Only Zhuge Jing managed to escape alive back to the Wu capital Jianye. Wang Hun's subordinate urged him to press on to attack Jianye immediately, but he refused under the excuse that he was ordered by Emperor Wu of Jin to secure the northern shore of Yangtze River only and wait for Wang Jun. Wang Hun was in fact, taking a more cautious approaching by attempting to join forces with Wang Jun to ensure the final victory, but such prudence cost him the glory of capturing the enemy capital city, the highest honor in the campaign.

Wang Jun's 80,000 strong army, meanwhile, reached Niuzhu (牛渚) on March 14, 280, after leaving Wuchang (武昌, present-day Ezhou, Hubei) and the Wu emperor Sun Hao ordered Zhang Xiang (張象) to lead a 10,000 strong navy to engage the enemy. However, when both fleets met, the demoralized Wu navy surrendered en masse, including Zhang Xiang himself. Wang Hun ordered Wang Jun to see him so that they could discuss their next move, but Wang Jun answered that his fleet had already passed Wang Hun's camp and could not turn back due to the current, and continued on toward Jianye.

As Wang Jun's forces advanced on to Sanshan (三山) on March 14, 280, just southeast of Jianye, Wu general Tao Jun (陶濬) organized a 20,000 strong army to make a last stand, but nearly all the Wu troops deserted on the very same night, and Tao Jun and his few "die-hard" followers were killed subsequently in their futile struggle against the Jin invaders. Sun Hao adopted a last attempt suggested by his subjects Xue Ying and Hu Chong (胡沖) by sending letters of surrender to Sima Zhou, Wang Jun and Wang Hun, in a move to stir up internal conflict among the Jin commanders in order to buy time, but such a tactic proved useless.

On March 15, 280, Sun Hao stripped all clothing on his upper body and tied himself up (a traditional way of presenting prisoners-of-war to the victors) and walked to Wang Jun's camp to surrender. Prior to that, Sun Hao issued his last imperial decree, asking his people not to be upset with the end of Wu, but prepare themselves to serve the new dynasty. Sun Hao was then taken to the Jin capital Luoyang with his imperial chariot, but was not allowed to ride on it. Instead, he travelled on foot as he was now a prisoner-of-war. After hearing of Sun Hao's surrender, the last pocket of Wu resistance in Jianping, led by Administrator Wu Yan (吾彥), followed suit even after having successfully defended against all Jin attacks throughout the campaign.

Aftermath
The fall of Jianye marked the end of Wu and the Three Kingdoms period, and China was unified again under the Jin Dynasty. The Jin commanders who participated in the campaign were handsomely rewarded, and ironically, Jia Chong, the overall commander who had opposed the campaign received the largest reward, the tax income of 8,000 households. Wang Hun was furious upon learning the news of Wang Jun taking Jianye, and angrily proclaimed to his subordinates that he had watched Sun Hao for nearly a hundred days, but Wang Jun took the advantage at last. Wang Hun wrote to the imperial court to complain, claiming that Wang Jun disobeyed orders and embezzled war spoils. Wang Jun also wrote to the imperial court to defend himself, claiming that what Wang Hun had said was slander. However, Wang Hun was much more powerful and influential in the Jin court, thus had gained an upper hand, with his followers suggesting that Wang Jun be jailed. In the end, Emperor Wu of Jin put an end to the conflict by rewarding Wang Jun handsomely.

Order of battle
To boost morale, some of the Jin commanders received new ranks, while in contrast, Wu did almost nothing to reinforce its own defense.

Jin forces

 * Grand Viceroy (大都督) Jia Chong
 * General of Champions (冠軍將軍) Yang Ji (楊濟), served as Jia Chong's deputy
 * Imperial Secretary of Budgeting (度支尚書) Zhang Hua, was in charge of supplies and logistics
 * Prince of Langya / General Who Stabilizes the Army (瑯琊王 / 鎮軍將軍) Sima Zhou, would attack Tuzhong (涂中) from Xiapi (下邳)
 * Chancellor of Langya (瑯琊相) Liu Hong (劉弘)
 * Chief Clerk (長史) Wang Heng (王恆)
 * General Who Pacifies the East (安東將軍) Wang Hun (王渾), would attack Hezhou (和州) from Yang Province (揚州)
 * General Who Protects the Army (護軍將軍) Zhang Han (張翰)
 * Inspector of Yang Province (揚州刺史) Zhou Jun (周濬)
 * Xue Sheng (薛勝)
 * Jiang Ban (蔣班)
 * Senior General Who Conquers the South (征南大將軍) Du Yu, would attack Jiangling (江陵) from Xiangyang (襄陽)
 * Army Advisor (參軍) Fan Xian (樊顯)
 * Army Advisor Yin Lin (尹林)
 * Army Advisor Deng Gui (鄧圭)
 * Administor of Xiangyang (襄陽太守) Zhou Qi (周奇)
 * General of the Standard (牙門將軍) Zhou Zhi
 * General Who Establishes Might (建威將軍) Wang Rong, would attack Wuchang (武昌; present-day Ezhou, Hubei) from Yu Province (豫州)
 * Army Advisor (參軍) Luo Shang (羅尚)
 * Army Advisor Liu Qiao (劉喬)
 * Commandant of Chengyang (成陽都尉) Zhang Qiao (張喬)
 * General Who Subdues the South (平南將軍) Hu Fen (胡奮), would attack Xiakou (夏口; present-day Wuchang District, Hubei) from Jing Province (荊州)
 * General of the Uplifting Dragon (龍驤將軍) Wang Jun, would attack downstream from Sichuan along the Yangtze River
 * General of Vast Martial (廣武將軍) Tang Bin (唐彬), defended Badong (巴東; present-day Fengjie County, Chongqing)

Before February 280

 * Grand Viceroy (大都督) Lu Yan (陸晏)
 * Lu Xuan (陸玄), served as Lu Yan's deputy
 * (P.O.W.) General of Military Might (武威將軍) Zhou Xing (周興)
 * (P.O.W.) Cai Ji (蔡機)
 * (P.O.W.) Supervisor of Danyang (丹楊監) Sheng Ji (盛紀)
 * General Who Stabilizes the South (鎮南將軍) Liu Xian (留憲)
 * General Who Conquers the South (征南將軍) Cheng Ju (成據)
 * Administrator of Yidu (宜都太守) Yu Zhong (虞忠)
 * Commander of Lexiang (樂鄉督) Sun Xin (孫歆)
 * Commander of Jiangling (江陵督) Wu Yan (伍延)
 * General of the Standard (牙門將軍) Meng Tai (孟泰)
 * Administrator of Wuchang (武昌太守) Liu Lang (劉朗)
 * Lu Jing, served as commander of the naval force (水軍都督)
 * Lu Ji, served as deputy commander of the naval force (水軍副督)

After February 280

 * Chancellor (丞相) Zhang Ti
 * Deputy Military Counselor (副軍師) Zhuge Jing (諸葛靓)
 * Administrator of Danyang (丹陽太守) Shen Ying (沈瑩)
 * General Who Protects the Army (護軍將軍) Sun Zhen (孫震)
 * General of Guerrilla Force (游擊將軍) Zhang Xiang (張象)
 * Commander of Xuling (徐陵督) Tao Jun (陶濬)
 * Administrator of Jianping (建平太守) Wu Yan (吾彥)

In fiction
In Luo Guanzhong's historical novel Romance of Three Kingdoms, the task of building a navy for the Jin Dynasty was credited to Zhong Hui before the fall of Shu, when Zhong recommended to Sima Zhao that constructing a large navy to attack Wu was a diversion to trick Shu into letting down its guard, and when it was time to truly attack Wu after the conquest of Shu, the navy would be ready. In reality, however, the idea of constructing a large navy originated from Wang Jun and Emperor Wu of Jin, and the plan was set into motion only after the fall of Shu.

In the novel, the last event before the campaign ended was described to be Zhang Xiang's surrender when he led a 10,000 strong navy to engage Jin forces. Since the Wu imperial court had not received news of Zhang Xiang's surrender yet, Wang Jun ordered Zhang Xiang to return to the Wu capital Jianye to trick the Wu defenders into opening the city gates. Zhang Xiang followed as instructed and Jin forces swiftly conquered Jianye. The Wu emperor Sun Hao surrendered and that marked the end of Wu. In history, however, before Sun Hao's surrender, there was one last battle at Sanshan (三山), just southeast of Jianye, between Wang Jun's army and a smaller force led by Wu general Tao Jun (陶濬).