The Chu–Han Contention (206–202 BC) was an interregnum between the Qin dynasty and the Han dynasty in Chinese history. Following the collapse of the Qin dynasty in 206 BC, Xiang Yu split the former Qin Empire into the Eighteen Kingdoms. Two major contending powers emerged, Western Chu and Han, which engaged in a struggle for supremacy over China. Western Chu was led by Xiang Yu, while the Han leader was Liu Bang. Several minor kings also warred, but these were largely independent of the main conflict between Western Chu and Han. The war ended in 202 BC with total victory for Han, with Liu Bang soon proclaiming himself first emperor of the Han dynasty.
In 221 BC, the Qin state unified China by conquering the other six major states and established the Qin dynasty. However, the oppressive and extremely unpopular dynasty lasted only 14 years. In 209 BC, Chen Sheng and Wu Guang started the Dazexiang Uprising to overthrow the Qin dynasty.
Although the uprising was crushed, several others erupted consecutively over the next three years. Numerous pretenders to the former six states emerged, the most powerful being the Chu kingdom. The Chu general Xiang Yu won the support of many rebel leaders after his victory at the Battle of Julu, becoming the de facto leader of the insurgents and proclaiming himself "Hegemon-King of Western Chu" (西楚霸王). He ruled nine commanderies in the former Liang and Chu territories, with his capital at Pengcheng (彭城; present-day Xuzhou, Jiangsu).
Xiang Yu divided up the former Qin Empire into vassals, the Eighteen Kingdoms, and gave the puppet ruler King Huai II of Chu a more honourable title, "Emperor Yi of Chu". About a year later, Xiang Yu effectively sent the figurehead into exile to Chen County (郴縣; present-day Chenzhou, Hunan), and secretly ordered Ying Bu (King of Jiujiang) to assassinate him on his way there.
During the division of the Eighteen Kingdoms, Xiang Yu appointed some former rebel generals as vassal kings even though they were subordinates of other lords. In 206 BC Liu Bang was deprived of his title in Guanzhong and instead sent to the remote Bashu region (巴蜀; in present-day Sichuan and Chongqing) along with 30,000 troops and thousands more civilians and given the title "King of Han" (漢王).
After reaching his destination, Liu Bang ordered the gallery roads leading into Bashu to be destroyed as a precautionary move against any possible attack from the rear and to trick Xiang Yu into thinking that he had no intention of leaving Bashu. In 206 BCE the last Qin emperor Ziying surrendered to Liu Bang and brought an end to the Qin dynasty.
Meanwhile, in the former Qi state, Tian Rong (Qi's chancellor) was unhappy with how the Qi territories were allocated, so he waged war against the kings of Jiaodong, Qi and Jibei (collectively known as the Three Qis). Tian Rong conquered the Three Qis and instated Tian Fu as the King of Qi, but later took over the throne himself.
Tian Rong put Peng Yue in charge of his army, ordering him to attack Western Chu, and sent troops to support another rebellion in the former Zhao state led by Chen Yu, a former Zhao vice-chancellor. In 205 BC, Chen Yu defeated Zhang Er (King of Changshan), seized his domain, and installed Zhao Xie (King of Dai) as the ruler of the Zhao territories. Xiang Yu felt threatened by the rebellions in Qi and Zhao so he led his forces to attack Tian Rong.
While Xiang Yu was away suppressing the rebellions, Liu Bang used the opportunity to attack the Three Qins in Guanzhong. Liu Bang's general Han Xin ordered his men to pretend to repair the gallery roads in order to put Zhang Han (King of Yong) off guard, while secretly making advances through Chencang (陳倉; present-day Chencang District, Baoji, Shaanxi). Zhang Han was taken by surprise and defeated by the Han forces in two consecutive battles.
Taking advantage of the victory, Liu Bang proceeded to conquer Longxi (隴西), Beidi (北地) and Shangjun (上郡). He also sent his men to fetch his family in Pei (沛; in present-day Xuzhou, Jiangsu). Upon receiving news of Liu Bang's attacks, Xiang Yu sent an army to Yangxia (陽夏) to intercept the Han army, and appointed Zheng Chang as the "King of Hán" to help him cover his flank. In Yan, Zang Tu killed Han Guang (King of Liaodong), seized his lands and proclaimed himself the ruler of the Yan territories.
In 205 BC, after establishing his base in Guanzhong, Liu Bang advanced to the east of Hangu Pass to prepare for an attack on the Henan region. Sima Xin (King of Sai), Dong Yi (King of Di) and Shen Yang (King of Henan) surrendered to Liu Bang. Zheng Chang (King of Hán) refused to submit to Liu Bang and was defeated by Han Xin in battle. Liu Bang replaced Zheng Chang with Hán Xin as the new King of Hán. Zhang Er (former King of Changshan) came to join Liu Bang after losing his domain to Zhao Xie and Chen Yu.
In the third month, Liu Bang attacked Henei (河內) with help from Wei Bao (King of Western Wei). When Liu Bang received news that Emperor Yi of Chu had been murdered on Xiang Yu's order, he held a memorial service for the emperor, accused Xiang of committing regicide, and used that incident as political propaganda to justify the war against Western Chu.
In the fourth month of 205 BC, Xiang Yu defeated Tian Rong at Chengyang (城陽). Tian Rong was killed while retreating to Pingyuan. Although the Qi kingdom had surrendered to Western Chu, Xiang Yu did not appease the people and instead allowed his soldiers to loot and plunder the Qi territories. Tian Rong's younger brother, Tian Heng, installed Tian Guang (Tian Rong's son) on the throne of Qi, and continued to put up resistance against Western Chu.
Meanwhile, Liu Bang had mustered an army of about 560,000 with support from the kings who surrendered to him. In the eighth month, Chu's capital, Pengcheng (彭城; present-day Xuzhou, Jiangsu), fell to a coalition force led by Liu Bang. When Xiang Yu received news that Liu Bang had occupied Pengcheng, he led 30,000 troops to retake Pengcheng. Liu Bang was caught off guard and his army suffered heavy casualties and his family members were captured by Chu forces. After the battle, Han lost its territorial gains in Chu and the support of its allies.
After their defeat at Pengcheng, the strength of the Han forces decreased drastically. Liu Bang's family members were captured by Chu forces and kept as hostages. Besides, many of the kings who had surrendered to Liu Bang earlier defected to Xiang Yu's side after Liu Bang's defeat. Moreover, the Qi and Zhao kingdoms, which were previously at war with Chu, also requested to make peace with Chu.
Upon reaching Xiayi (下邑; east of present-day Dangshan County, Suzhou, Anhui), which was defended by his brother-in-law, Liu Bang reorganised his troops for a retreat. When he arrived at Yu (虞; present-day Yucheng County, Shangqiu, Henan), he sent an envoy to meet Ying Bu (King of Jiujiang) and persuade Ying to support him. Ying Bu agreed to join Liu Bang and rebelled against Western Chu. Xiang Yu sent Long Ju to lead an army to attack Ying Bu.
In the sixth month of 205 BCE, Liu Bang named his son Liu Ying as his crown prince and ordered him to defend Yueyang (櫟陽; present-day Yanliang District, Xi'an, Shaanxi). Shortly after, Han forces conquered Feiqiu (廢丘; present-day Xingping, Shaanxi), which was guarded by Zhang Han, who committed suicide after his defeat.
On another front, Ying Bu was unable to defeat Long Ju so he gave up on Jiujiang and went to join Liu Bang. Liu Bang reorganised his army, which now included reinforcements from Guanzhong (sent by Xiao He) and Han Xin's troops. Liu Bang's forces attacked Chu at Jing County (京縣; around present-day Xingyang, Zhengzhou, Henan) and Suoting (索亭; near present-day Xingyang, Henan), emerged victorious, and drove Xiang Yu's forces east of Xingyang.
In 205 BC, Wei Bao (King of Wei) left Liu Bang on the pretext of visiting an ill relative and secretly returned to his domain. He pledged allegiance to Xiang Yu and rebelled against Liu Bang. Liu Bang sent Li Yiji to persuade Wei Bao to surrender but Wei refused, so Liu ordered Han Xin to lead an army to attack Wei.
Wei Bao stationed his army at Puban (蒲阪) and blocked the route to Linjin (臨晉). Han Xin tricked Wei Bao into believing that he was planning to attack Linjin, while secretly sending a force from Xiayang (夏陽) to cross the river and attack Anyi (安邑; present-day Xia County, Yuncheng, Shanxi). In the ninth month, Wei Bao personally led an attack on Han Xin but lost the battle and was captured. When he offered to surrender, Liu Bang accepted his surrender and appointed him as a general. In the ninth month, Han Xin led his army to attack the Kingdom of Dai with support from Zhang Er (former King of Changshan), scored a decisive victory against Dai, and captured Dai's chancellor, Xia Shuo.
After achieving victory over the Dai kingdom, Han Xin and Zhang Er led an army to attack the Zhao kingdom at Jingxing Pass. Zhao Xie (King of Zhao) and his chancellor, Chen Yu, led an army of 200,000 to resist the Han forces. The Zhao general Li Zuoche proposed a plan to trap Han Xin within 10 days: he would lead 30,000 men to disrupt Han Xin's supply route and block his return route, while Chen Yu would defend the frontline firmly and prevent Han Xin from advancing. Chen Yu refused to implement Li Zuoche's plan.
The evening before the battle, Han Xin sent 2,000 horsemen, each carrying a flag of the Han army, to station near the Zhao camp. The next morning, Han Xin feigned defeat in a skirmish with Zhao forces and lured them to follow him, while his 2,000 men took advantage of the situation to capture the weakly defended Zhao camp. Meanwhile, the Zhao soldiers retreated after failing to conquer Han Xin's fort, and were surprised to see that their camp had been occupied by Han forces when they returned. The Zhao army fell into chaos and Han Xin seized the opportunity to launch a counterattack and scored a victory. Chen Yu was killed in action while Zhao Xie and Li Zuoche were captured.
In 204 BC, the Yan kingdom surrendered to Han Xin, and Zhang Er was appointed as the King of Zhao. Xiang Yu constantly sent his armies to attack Zhao but Han Xin and Zhang Er managed to hold their ground. Xiang Yu then turned his attention towards Xingyang, where Liu Bang was stationed. Liu Bang was forced to retreat to Chenggao, where he was besieged by Xiang Yu. Eventually, he had no choice but to head north of the Yellow River to join Han Xin. In a surprise move, Liu Bang took over Han Xin and Zhang Er's command of the Han army in Zhao. He then ordered Han Xin to lead an army to attack the Qi kingdom.
Just as Han Xin was preparing to attack Qi, Liu Bang sent Li Yiji to persuade Tian Guang (King of Qi) to surrender without informing Han Xin. Tian Guang decided to surrender and ordered his troops to withdraw from Lixia (歷下; present-day Lixia District, Jinan, Shandong). However, Han Xin was not aware that Tian Guang had the intention of surrendering, so he followed Kuai Tong's advice to attack Qi. Han Xin's army conquered Lixia and attacked the Qi capital, Linzi. Tian Guang thought that Li Yiji had lied to him so he executed Li and retreated to Gaomi, where he requested aid from Western Chu. Meanwhile, Han Xin conquered Linzi and continued to pursue the retreating Qi forces to Gaomi.
Xiang Yu sent Long Ju to lead 200,000 troops to help Tian Guang. The allied forces of Qi and Chu lost to Han in the first battle. Someone advised Long Ju to avoid engaging Han Xin directly and focus on strengthening their defences, while asking Tian Guang to rally support from the Qi cities that had fallen to Han. In that case, the Han army would eventually be deprived of supplies and be forced to surrender. However, Long Ju rejected the plan and insisted on attacking Han Xin. On the night before the battle, Han Xin sent his men to dam the Wei River (濰水) with sandbags. The next morning, after a skirmish with Long Ju's forces, Han Xin feigned defeat and retreated to lure Long to follow him. When about a quarter of the Chu army had crossed the river, Han Xin signalled to his men to open the dam. Many Chu soldiers drowned and Long Ju was isolated with only a fraction of his forces. Taking advantage of the situation, Han Xin launched a counterattack. Long Ju was killed in action and the rest of the Chu army disintegrated as Han Xin continued pressing the attack. Tian Guang fled. Han Xin pursued the retreating enemy forces to Chengyang (城陽).
After his victory, Han Xin swiftly took control of the Qi territories and then sent an envoy to Liu Bang to request that Liu appoint him as the King of Qi. At the time, Liu Bang was besieged in Xingyang by Xiang Yu, and was eagerly waiting for reinforcements from Han Xin. He was furious when he received Han Xin's request. However, eventually, acting on the advice of Zhang Liang and Chen Ping, Liu Bang reluctantly approved Han Xin's request. At the same time, Xiang Yu felt worried after losing Long Ju, so he sent Wu She to attempt to persuade Han Xin to rebel against Liu Bang and declare himself king. However, despite urging from Kuai Tong, Han Xin refused to betray Liu Bang. Han Xin later organised an army to move southward and attack Western Chu.
On the southern front, Liu Bang's forces started building supply routes from Xingyang to Aocang (敖倉). In 204 BC, after sustaining losses from Chu attacks on the routes, the Han army was running short of supplies. Liu Bang negotiated for peace with Xiang Yu and agreed to cede the lands east of Xingyang to Western Chu. Xiang Yu wanted to accept Liu Bang's offer, but Fan Zeng advised him to reject and use the opportunity to destroy Liu Bang. Xiang Yu changed his mind, pressed the attack on Xingyang and besieged Liu Bang's forces inside the city. Liu Bang heeded Chen Ping's suggestion to bribe Xiang Yu's men with 40,000 catties of gold for them to spread rumours that Fan Zeng had the intention of betraying Xiang Yu. Xiang Yu fell for the ruse and dismissed Fan Zeng.
In late 204 BC, while Xiang Yu was away suppressing the rebellion in the Qi kingdom, Li Yiji advised Liu Bang to use the opportunity to attack Western Chu. Han forces conquered Chenggao and defeated the Chu army led by Cao Jiu near the Si River. Liu Bang's forces advanced further until they reached Guangwu (廣武). Chu forces led by Zhongli Mo were trapped by the Han army at the east of Xingyang. Following Han Xin's victory in the Battle of Wei River, the Chu army's morale fell and it ran short of supplies months later. Xiang Yu had no choice but to request to make peace with Liu Bang and release Liu's family members, who were held hostage by him. Chu and Han agreed to a ceasefire at the Treaty of Hong Canal (鴻溝和約), which divided China into east and west under their respective domains.
In 203 BC, while Xiang Yu was retreating eastward, Liu Bang, acting on the advice of Zhang Liang and Chen Ping, renounced the Treaty of Hong Canal and ordered an attack on Western Chu. He also requested assistance from Han Xin and Peng Yue to attack Xiang Yu simultaneously from three directions. However, Han Xin and Peng Yue did not mobilise their troops and Liu Bang was defeated by Xiang Yu at Guling (固陵; south of present-day Taikang County, Zhoukou, Henan). Liu Bang retreated and reinforced his defences. At the same time, he sent messengers to meet Han Xin and Peng Yue again, and promised to give them land and titles if they joined him in attacking Xiang Yu.
Three months later, in 202 BC, Han forces led by Liu Bang, Han Xin and Peng Yue attacked Western Chu from three directions. The Chu army was running low on supplies and Xiang Yu was trapped in Gaixia (垓下; southeast of present-day Lingbi County, Suzhou, Anhui). Han Xin ordered his troops to sing Chu folk songs to create a false impression that Chu had fallen to Han forces. The Chu army's morale plummeted and many soldiers deserted.
Xiang Yu attempted to break out the siege and was left with only 28 men when he reached the northern bank of the Wu River (near present-day He County, Chaohu City, Anhui). He made a last stand and managed to slay several Han soldiers before eventually committing suicide.
After Xiang Yu's death, the rest of Western Chu surrendered to Han, and China was unified under Han rule. Liu Bang granted Peng Yue, Ying Bu and Han Xin the titles "King of Liang", "King of Huainan" and "King of Chu" respectively. Months later, at the urging of his followers and vassals, Liu Bang declared himself Emperor and established the Han dynasty. He built his capital in Luoyang (later moved to Chang'an) and named Lü Zhi his empress, and Liu Ying as his crown prince.
Although Liu Bang initially handsomely rewarded his subjects who helped him become the Emperor, he gradually became suspicious of them over time and started to doubt their loyalties. Han Xin was demoted from "King of Chu" to "Marquis of Huaiyin" in late 202 BC, and was subsequently arrested and executed by Empress Lü in 196 BC for allegedly plotting a rebellion with Chen Xi. In the same year, Liu Bang believed rumours that Peng Yue was also involved in the plot, and demoted Peng to the status of a commoner. Peng Yue and his family members were subsequently executed by Empress Lü.