Conquest of Wu by Jin

Map of China divided between the Jin dynasty (blue) and Eastern Wu (red) in the year 266.

Following the end of the Eastern Han dynasty in 220,[6] three contending states emerged in China and fought for control over the territories of the former Han Empire. Among the three, Wei was the most powerful one in terms of military prowess, economic resources, manpower and geographical size. The other two, Shu and Wu, reestablished their alliance against Wei in 223.[7]

From as early as 262, the Wei regent Sima Zhao had already started planning for the conquests of Wei's two rival states. He decided to attack Shu first because an invasion of Wu required costly and labour-intensive preparations such as constructing naval vessels and opening up waterways for the vessels. He also pointed out that if Wei managed to conquer Shu, they could make use of Shu's geographical advantage by sending a naval fleet downstream from Shu to attack Wu.[8] In the winter of 262, as the Wei government mobilised troops from the various provinces for the Shu invasion, they also put Tang Zi in charge of overseeing the construction of warships in preparation for a future invasion of Wu.[9]

In early 266, about two years after the surrender and end of Shu, Sima Zhao's son and successor Sima Yan usurped the throne from the last Wei emperor Cao Huan and established the Jin dynasty to replace Wei.[10] During this time, Sima Yan heeded his advisers' suggestions to win over the Shu people's hearts by showing benevolence and generosity, as well as to induce Wu subjects to defect to Jin by tempting them with rewards and incentives. Among other things, he made the former Shu emperor Liu Shan a duke, and awarded peerages, titles and appointments to numerous former Shu subjects and their descendants, including Luo Xian, Chen Shou, Zhuge Jing, Lü Ya, Fei Gong and Chen Yu.[11][12][10]

On 29 April 269, Sima Yan ordered Yang Hu to station at Xiangyang and supervise military affairs in the Jin-controlled territories in Jing Province.[10]

In 264, following the Wu emperor Sun Xiu's death, his nephew Sun Hao came to the throne.[13] In the same year, the Wei regent Sima Zhao sent two former Wu officers Xu Shao (徐紹) and Sun Yu (孫彧), who defected to Wei during the Shouchun rebellion, to deliver a letter to Sun Hao.[14] In the letter, Sima Zhao pointed out that Wu stood no chance against a Wei invasion and told Sun Hao that he would be treated generously if he surrendered.[15]

Around April 265, Sun Hao sent Ji Zhi (紀陟) and Hong Qiu (弘璆) as his emissaries to meet Sima Zhao, and express his desire for Wei and Wu to coexist peacefully.[16] Ji Zhi and Hong Qiu accomplished their diplomatic mission well and even impressed Sima Zhao with their replies to questions from various Wei officials.[17]

Sima Zhao died in September 265. In February 266, after Sima Zhao's eldest son Sima Yan usurped the Wei throne and established the Jin dynasty,[10] Sun Hao sent Zhang Yan (張儼) and Ding Zhong (丁忠) as his representatives to attend a memorial service for Sima Zhao.[18] After Ding Zhong returned, he advised Sun Hao to launch an attack on the Jin-controlled Yiyang Commandery (弋陽郡; around present-day Xinyang, Henan) because it was poorly guarded. When Sun Hao consulted his subjects, Lu Kai and Liu Zuan opposed and supported launching the attack respectively. Sun Hao secretly desired to heed Ding Zhong's suggestion but ultimately dropped the idea after considering the recent fall of Wu's ally state Shu.[19]

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 defences 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 government had already lost the popular support of the people, and many regional commanders stationed at the border defected to the Jin dynasty.

At the same time, Sima Yan sent envoys to Wu to cease hostilities between the two states, in order to buy time for making preparations. The Wu emperor emperor Sun Hao, in turn, viewed such actions as a sign of weakness of the Jin dynasty, and further let down his guard.

In 272, Yang Hu pointed out to Sima Yan that their forces could take advantage of their position in Yi Province and send a naval fleet downstream along the Yangtze to attack Wu. He secretly recommended to the emperor to appoint Wang Jun, who previously served as an army adviser under him, to serve as the Inspector of Yi Province (益州刺史) and oversee the construction of a naval fleet. Shortly after he was appointed as the Inspector of Yi Province, Wang Jun was also commissioned as Prancing Dragon General (龍驤將軍) and put in charge of supervising military affairs in Yi and Liang provinces.[22]

Wang Jun reassigned his troops from farming in the agricultural colonies to start building vessels for the upcoming naval invasion of Wu. During this time, Wang Jun's assistant He Pan pointed out that they needed to recruit at least 10,000 labourers from every commandery in Yi Province for the project, which could be completed within a year. He Pan also advised Wang Jun to notify the central government after they had started the project because the central government might reject their idea of recruiting 10,000 labourers from every commandery. Wang Jun heeded He Pan's advice.[23]

To make up for the Jin navy's lack of experience in naval warfare in comparison to the Wu navy, Wang Jun constructed many large vessels equipped with ram bows. The largest of these vessels were 120 bu long and capable of carrying up to 2,000 troops on board. These vessels also had viewing towers and three-storey-tall fortifications made of strong wood. In addition, the vessels had doors on all four sides to allow troops to board and get off easily. Horses could even run freely on board.[24] It took Wang Jun a total of seven years to build the naval fleet and the only thing left to do was to train his troops in naval warfare.

In November or December 276,[25] Yang Hu wrote a memorial to Sima Yan to outline a plan for the conquest of Wu as follows: Jin forces in Yi Province to attack Wu from the west on both land and water; Jin forces in Jing Province to attack Jiangling; Jin forces in Yu Province to attack Xiakou; and Jin forces in Xu, Yang, Qing and Yan provinces to attack Moling. He explained that the idea of invading Wu from multiple directions was to confuse the Wu forces and demoralise the Wu forces by creating the impression of an overwhelming invasion. He further pointed out Wu's only strategic advantage was the Yangtze, which served as a natural barrier. However, once the Jin forces break through the Wu defences along the Yangtze, the Wu forces would retreat to behind their walled cities and fortresses. By then, the Jin forces, which were more adept in land-based warfare, would gain the upper hand over their adversaries. He also noted that Sun Hao was a highly unpopular ruler among his people and that a Jin invasion would provide a long-awaited opportunity for many Wu subjects to defect to the Jin side.[26]

Sima Yan strongly agreed with Yang Hu's views and wanted to implement the plan. When Yang Hu's plan was put up for discussion in the Jin imperial court, many officials, including Jia Chong, Xun Xu and Feng Dan, argued that it was not time to attack Wu yet because they had to deal with the Xianbei rebels in Yong and Liang provinces. Only Du Yu and Zhang Hua supported Yang Hu's proposal.[27]

In July or August 278, due to poor health, Yang Hu left his post at Xiangyang and moved to Luoyang to recuperate. When Sima Yan sent Zhang Hua to visit him, Yang Hu told Zhang Hua that they should seize the opportunity to conquer Wu while Sun Hao was still in power since Sun Hao's tyranny had already caused him to lose popular support from the Wu people. He also recommended Du Yu to replace him as the general overseeing military affairs in Jing Province.[28] He died on 27 December 278.[25]

In October 276, the preparation was roughly completed and Yang Hu suggested to Sima Yan to launch the attack. Yang Hu's suggestion was initially accepted but then delayed due to Jia Chong's objection, because the Xianbei tribes in northwestern China had started a rebellion. In July 277, additional assignments were given in order to prepare for the campaign against Eastern Wu:

• Wang Hun (王渾) was put in charge of military affairs of Yang Province
• Sima Liang was put in charge of military affairs of Yu Province
• Hu Fen (胡奮) was put in charge of military affairs along the northern shore of the Yangtze River

After Yang Hu's death, Du Yu succeeded him and was appointed Senior General Who Conquers the South (征南大將軍) to take charge of military affairs in Jing Province from November 278.

Since the Wu emperor Sun Hao did not believe that the Jin dynasty 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 defences 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.

After conquering Danyang, the Jin naval fleet continued its journey downstream and arrived at Xiling Gorge, where they encountered the blockade set up earlier by Wu Yan. Wu Yan had ordered his troops to connect an array of iron awls, each measuring more than one zhang, with heavy iron chains and put them into the water to block enemy vessels from passing through.[38] However, the Jin naval fleet knew about the blockade through intelligence gathered earlier by Yang Hu from captured Wu spies, so they were prepared to deal with the situation.[39]

Wang Jun ordered his men to build a dozen large rafts, each over 100 bu wide, and place straw dummies on them. He also ordered large torches, each measuring over ten zhang in length and over ten wei in circumference, to be placed in front of every raft and drenched in oil. He then deployed the rafts ahead of his fleet towards the blockade. When the rafts became stuck in the blockade, Wang Jun ordered his men to set the rafts on fire. After burning for several hours, the iron awls and chains melted and cleared the way for the Jin naval fleet to pass through.[40]

On 20 March 280, Wang Jun and his forces conquered Xiling (西陵; around present-day Yichang, Hubei) and killed the Wu officers Liu Xian (留憲), Cheng Ju (成據) and Yu Zhong.[41] Two days later, they seized control of Jingmen and Yidao (夷道; present-day Yidu, Hubei) and killed the Wu officer Lu Yan.[42]

When Wang Jun conquered Xiling, Du Yu wrote to him to give him the green light to advance further east along the Yangtze and conquer Moling (秣陵; present-day Nanjing, Jiangsu), the Wu capital. Wang Jun was so pleased after reading Du Yu's letter that he sent it to the Jin emperor Sima Yan.[43]

Du Yu also sent Zhou Zhi (周旨), Wu Chao (伍巢) and Guan Ding (管定) to lead 800 soldiers to cross the Yangtze at night and prepare for an attack on Lexiang (樂鄉; east of present-day Songzi, Hubei). When they reached Mount Ba (巴山; southwest of present-day Songzi, Hubei), they started many fires and planted many flags around the area to mislead the Wu defenders into thinking that the Jin army was larger than it actually was. At the same time, they raided key locations around Lexiang to confuse and strike fear in the enemy. Sun Xin, the Wu officer guarding Lexiang, felt so shocked and terrified that he wrote to Wu Yan (伍延), the Wu officer defending Jiangling County, as follows: "The armies coming from the north must have flown across the river."[46]

Zhou Zhi, Wu Chao and Guan Ding led their 800 men to lay in ambush outside Lexiang. In the meantime, as Wang Jun's naval fleet was approaching Lexiang from the west along the Yangtze, Sun Xin sent troops out of Lexiang to drive back the enemy but they failed. When Sun Xin's defeated troops returned to Lexiang, the three Jin officers and their 800 men used the opportunity to infiltrate the city without being detected. They swiftly seized control of Lexiang, captured Sun Xin in his own camp, and sent him as a captive to Du Yu.[47]

On 25 March 280, the Jin forces occupied Lexiang and killed the Wu naval officer Lu Jing. Shi Hong (施洪), a Wu general, surrendered to them.[48]

When Du Yu ordered his troops to increase the intensity of their attacks on Jiangling County, Wu Yan pretended to surrender to Du Yu while instructing his men to stand on guard at the top of the city walls. On 3 April 280, Du Yu managed to break through Wu Yan's defences and conquer Jiangling County. Wu Yan was killed in battle.[49]

Around the same time, the Jin army led by Hu Fen also conquered Jiang'an (江安; present-day Gong'an County, Hubei).[50]

Between 17 and 30 April 280, the Wu emperor Sun Hao ordered his chancellor Zhang Ti and the generals Shen Ying (沈瑩), Zhuge Jing and Sun Zhen to lead an army of 30,000 from Moling (秣陵; present-day Nanjing, Jiangsu) and cross the Yangtze to attack the Jin invaders.[60] When they reached Niuzhu (牛渚; in present-day Ma'anshan, Anhui), Shen Ying predicted that the Jin naval fleet would eventually break through the Wu defences in Jing Province, so he advised Zhang Ti to adopt a defensive stance by holding their positions at the lower reaches of the Yangtze and prepare to make a final stand when the Jin naval fleet showed up.[61] Zhang Ti, however, argued that the Wu army's morale would collapse if the Jin naval fleet managed to make its way to Moling, so they should strike back at the Jin invaders. From his point of view, if the Wu army succeeded in driving back the Jin invaders or at least preventing them from advancing further, they could then join forces with the remaining Wu forces in Jing Province and strengthen their defences.[62]

In mid-April 280, Zhang Ti led the Wu forces to attack the Jin officer Zhang Qiao (張喬), who had 7,000 troops with him, near Yanghe Bridge (楊荷橋; southeast of present-day He County, Anhui). After Zhang Qiao surrendered,[63] Zhuge Jing urged Zhang Ti to execute all the captives because he believed that they were pretending to surrender. He also warned Zhang Ti that the surrendered Jin soldiers could potentially pose a threat to them later. Zhang Ti refused to heed Zhuge Jing's suggestion as he thought that it was unwise to execute enemy soldiers who surrendered.[64]

When Wang Hun learnt of the Wu attack at Yanghe Bridge, he ordered his subordinates Zhang Han (張翰), Sun Chou (孫疇) and Zhou Jun[65] to lead troops to resist the Wu army.[66] At Ban Bridge (版橋; north of present-day Hanshan County, Anhui), both sides got into their battle formations and prepared to fight. During the battle, Shen Ying led 5,000 members of the Wu army's elite "Danyang Corps" (丹陽兵) and charged into the Jin formation several times but the Jin forces managed to hold their ground. The rest of the Wu army felt demoralised upon seeing the failure of the "Danyang Corps" to break the Jin formation so they became chaotic and disorganised when their commanders called for a retreat. Two Jin officers, Xue Sheng (薛勝) and Jiang Ban (蔣班), seized the opportunity to lead their units to launch a fierce counterattack on the enemy. The Wu army fell apart as the soldiers scattered and fled in different directions while their commanders failed to stop them from deserting. At the same time, the Jin officer Zhang Qiao and his men, who had surrendered to the Wu army earlier, capitalised on the momentum to turn against their captors and attack them from the rear. The Wu generals Sun Zhen and Shen Ying, along with 7,000 to 8,000 Wu soldiers, perished in the battle.[67][68][69]

The Wu general Zhuge Jing, who managed to flee the battlefield with 500 to 600 men, encountered Zhang Ti along the way and asked him to join them in retreating back to Moling. When Zhang Ti declined, Zhuge Jing held him and told him there was no need to seek death. However, Zhang Ti firmly refused to flee to because he wanted to fulfil his allegiance to Wu. Zhuge Jing had no choice but to tearfully let him go. After Zhuge Jing retreated further by about 100 bu (paces), the pursuing Jin soldiers caught up with Zhang Ti and killed him.[70]

Shortly after the Battle of Ban Bridge, the Wu minister He Zhi (also Sun Hao's maternal uncle) and general Sun Yan (孫晏) surrendered to the Jin army under Wang Hun.[71]

After the Jin victory at Ban Bridge, Zhou Jun's subordinate He Yun advised him to lead their troops across the Yangtze and besiege the Wu capital Moling (秣陵; present-day Nanjing, Jiangsu) so as to pressure the Wu emperor Sun Hao into voluntarily surrendering.[72] Zhou Jun agreed with He Yun and wanted to propose this idea to his superior, Wang Hun. However, He Yun predicted that Wang Hun would not agree because he was not authorised by the Jin emperor Sima Yan to attack Moling.[73] He Yun was proven right later; Wang Hun stubbornly refused to launch an attack on Moling even after Zhou Jun and He Yun urged him to.[74]

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