Xiang Yu's arrangement of the
Eighteen Kingdoms sowed significant dissatisfaction among the anti-Qin rebels as it was marred by
cronyism, with many rebel leaders who were either not favored by Xiang Yu or merely absent during the appointment (as they were garrisoned far away from Guanzhong) receiving little to no fiefs at all. His enfeoffment of the
Guanzhong region (which rightfully should have been Liu Bang's) to three surrendered Qin generals
Zhang Han,
Sima Xin and
Dong Yi (collectively known as the
Three Qins), who were widely seen as
traitors by the Qin people after the sacking of Xianyang, essentially destabilized three of the Eighteen Kingdoms from the start. Moreover, the instigated assassination of
Emperor Yi, and Xiang Yu's personal arrogance over battlefield prowess and lack of respect for those deemed beneath him further added to the dissents.
Rebellions in Qi, Zhao and Yan Merely six months after Qin dynasty's collapse,
Tian Rong, a
Qi state noble and rebel leader, was unhappy with how the Qi territories had been split among three kingdomsQi, Jiaodong and Jibei, collectively known as the Three Qis and himself not receiving anything due to grudges with Xiang Yu, so he waged war against the other kingdoms. He killed Tian Shi, the King of Jiaodong, and Tian An, the King of Jibei. Tian Du, the King of Qi, was defeated by Tian Rong so he fled and joined Xiang Yu. Tian Rong gained control of the Three Qis and became the ruler of the Qi territories. Tian Rong contacted
Peng Yue, a
grassroots rebel leader who also didn't go to Guanzhong to be enfeoffed and ended up with his territory claimed by Xiang Yu, and formed an alliance against Xiang Yu. At the same time, he sent troops to support
Chen Yu, who had started a rebellion in the former
state of Zhao. In 205 BCE, Chen Yu defeated
Zhang Er, the King of Changshan, and seized control of his kingdom. Chen Yu then installed
Zhao Xie, the King of Dai, as the new ruler of the Zhao territories. Upon learning of the rebellions in Qi and Zhao, Xiang Yu led his forces north to deal with the rebels. Meanwhile, further in the north,
Zang Tu, the King of
Yan, killed
Han Guang, the King of
Liaodong, seized the latter's lands and proclaimed himself the ruler of the Yan territories.
Han conquest of the Three Qins While Xiang Yu was away and busy dealing with the northern rebellions, Liu Bang, who was never happy with the fiefs forcefully appointed to him, seized the opportunity to attack the
Three Qins' territories in
Guanzhong. During the few months settling in Hanzhong, Liu Bang's deputy
Xiao He discovered a talented military commander named
Han Xin, and convinced Liu Bang to make him the
grand marshall. Han Xin proposed a strategy of pretending to reconstruct the previously burnt
gallery roads in order to draw the Three Qins' attention towards the
mountain passes south of Xianyang, while his main forces secretly took a western detour to invade Guanzhong through
Chencang (present-day
Baoji,
Shaanxi) and surprise the Three Qins. The plan was a huge success, and Han Xin defeated the hastily regrouped
Zhang Han, the King of Yong, in two consecutive battles. Riding on the tide of victory, Liu Bang proceeded to conquer
Longxi (the area in present-day eastern
Gansu located west of
Mount Long),
Beidi (northeastern Gansu and
Ningxia) and
Shang (around present-day
Yulin). He also sent his men to retrieve his family in
Pei (present-day
Xuzhou, Jiangsu) and bring them to him from territories controlled by Western Chu. Upon receiving news of Liu Bang's attacks, Xiang Yu sent an army to Yangjia (; present-day
Taikang County, Henan) to block Liu Bang's forces; he also appointed
Zheng Chang as the King of
Hán to help him cover his flank.
Battle of Pengcheng In 205 BCE, after conquering the Three Qins in the Guanzhong region, Liu Bang advanced to the east of
Hangu Pass to prepare for an attack on the
Henan region.
Sima Xin, the King of Sai,
Dong Yi, the King of Di, and
Shen Yang, the King of Henan, surrendered to Liu Bang.
Zheng Chang, the King of
Hán, refused to submit to Liu Bang, so Liu Bang sent
Hán Xin to attack and defeat him. Liu Bang then replaced Zheng Chang with Hán Xin as the new King of Hán.
Zhang Er, the former King of Changshan, joined Liu Bang after losing his domain to
Zhao Xie and Chen Yu. In April–May 205 BCE, Liu Bang attacked
Henei with help from
Wei Bao, the King of
Western Wei. When Liu Bang received news that Xiang Yu had ordered the assassination of
Emperor Yi, he held a memorial service for the emperor and accused Xiang Yu of committing
regicide, using this incident as political propaganda to justify his war against Xiang Yu. In May–June 205 BCE, Xiang Yu defeated
Tian Rong at Chengyang (; around present-day
Ju County, Shandong). Tian Rong was killed while retreating to
Pingyuan (around present-day northwestern Shandong). Although the Kingdom of Qi had surrendered, Xiang Yu still allowed his troops to plunder and loot the Qi territories. Tian Rong's younger brother,
Tian Heng, made Tian Rong's son
Tian Guang the new King of Qi, and continued to put up resistance against Xiang Yu. Meanwhile, Liu Bang had mustered an army of about 560,000 with support from the kings who had surrendered to him. In September–October 205 BCE, the Chu capital, Pengcheng (; 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. His army suffered heavy casualties, and his family members were captured by Chu forces. After the battle, Liu Bang lost his territorial gains in Chu and the support of his allies.
Battle of Jingsuo After their defeat at Pengcheng, the strength of the Han forces decreased drastically. Liu Bang's family members were captured by Xiang Yu's forces and kept as hostages. Many of the kings who had surrendered to Liu Bang earlier defected to Xiang Yu's side after Liu Bang's defeat. The rulers of Qi and Zhao also requested to make peace with Xiang Yu. Upon reaching Xiayi (; east of present-day
Dangshan County, Anhui), which was guarded by his brother-in-law, Liu Bang reorganised his troops for a retreat. Meanwhile, Han Xin led reinforcements from Guanzhong into central China and defeated a Chu army between Jing County () and Suo Village (), both in present-day
Henan. He also put down a rebellion by Wang Wu and Cheng Chu – former Qin generals – and Shen Tu, the magistrate of Wei, and captured their base at Waihuang (; in present-day
Minquan County, Henan). He and Liu Bang reorganised the Han army and established strong Han garrisons in Xingyang and
Chenggao. Han Xin also developed his plan to conquer northern China, with the aim that Xiang Yu would be too distracted by Liu Bang and his bases of Xingyang and Chenggao to properly counter Han Xin in the north, nor could he endanger his line of retreat by marching past Xingyang and Chenggao into Guanzhong. Liu Bang then sent a messenger to meet
Ying Bu, the King of Jiujiang, to persuade Ying Bu to support him. In November 205 BCE, after Han Xin's victory at the
Battle of Jingxing, Ying Bu agreed to join Liu Bang and rebelled against Xiang Yu. Upon learning about it, Xiang Yu sent
Long Ju to attack Ying Bu. In July–August 205 BCE, Liu Bang named his son
Liu Ying as his heir apparent and put him in charge of Yueyang (; present-day
Yanliang District, Xi'an). Shortly after, Han forces conquered Feiqiu (; present-day
Xingping, Shaanxi), which was guarded by
Zhang Han, who committed suicide after his defeat. On another front, Ying Bu was unable to resist Long Ju's attacks, so he abandoned his domain in Jiujiang and joined Liu Bang. == Northern front ==