For these reasons, Liu Bang had a strong claim to Guanzhong, which was grain-rich, populous, easily defensible and ideal for expansion into China's Central Plain.

After reaching the Han River Basin in Hanzhong, Liu Bang, on the advice of his advisor Zhang Liang, burned the wooden gallery road to prove his commitment to follow Xiang Yu's orders and remain within his own dominion.

[5] Xiang Yu thus recognized Zhang Han's talent and tasked him with defending the passes of the Qinling Mountains should Liu Bang attempt to re-cross north into Guanzhong from Hanzhong to the south.

[7] Confronted by the sheer distance between Hanzhong and their homeland of Chu in eastern China, Liu Bang's army and its leadership suffered from supply shortages and mass desertions.

[9] In early 206 Han Xin was a logistics prefect, and in this capacity he impressed Liu Bang's Prime Minister Xiao He, perhaps because he performed exceptionally well in securing and transporting the food resources of Ba and Shu from the far south-west of China to the army's position in Hanzhong.

By conquering the Three Qins so quickly, they could capitalize on the fact that Zhang Han, Sima Xin and Dong Yi had not ruled the region for very long.

He also sent Fan Kuai with a diversionary force along Qishan Road in the far-west, who defeated the Assistant Prefect of Xi County north of the Pai River.

They killed the guards and opened the gates, allowing Han Xin to march on the town of Chencang on the southern edge of Guanzhong's Wei River Basin.

A siege of Feiqiu could stall the progress of the invasion and give Zhang Ping, Sima Xin, Dong Yi and Xiang Yu himself more opportunity to crush the Han army before they had taken control of much of Guanzhong.

Fan Kuai reached the vicinity of Yong as well and defeated a force of cavalry and chariots to the south of the town before re-joining the main Han army.

They captured the two towns, with Fan Kuai seizing the walls with his vanguard, and they then pursued Zhang Ping, defeating him in a battle outside Haozhi.

[17][18] Sima Xin sent General Zhao Ben to reinforce Zhang Han in Feiqiu, and an army sent by Dong Yi arrived in the area of the Jingshui River.

Previously, Zhang Han had won both the battles of Linji (208) and Dingtao (208) by making surprise marches against the enemy position after appearing to be at a disadvantage.

Zhang Han returned to Feiqiu, and Zhao Ben withdrew further east to the former Qin capital Xianyang, which was being garrisoned by Sai troops under Neishi Bao.

The Sai army under Zhao Ben and Neishi Bao left the city to do battle with Han Xin but were defeated and fled east, causing Xianyang as well as the counties of Mei, Huaili and Liuchung to surrender.

[27] By June Han Xin had taken command of the siege of Feiqiu, and he ordered Fan Kuai to dig a channel from the Wei River to divert water to the mudbrick walls of the city.