Xiang Yu and Liu Bang agreed in the anti-Qin war that the first to attack Xianyang was king. In 207 BC, Liu Bang was the ancestor of Xianyang, but fearing that there were many people in Xiang Yu, he had to seal the treasure of Qin State, quit Xianyang and station troops. Xiang Yu, a native of Xianyang, set fire to Epang Palace, established himself as the overlord of "Western Chu", named Liu Bang as Hanwang, and named Zhang Han, Sima Xin and Dong Kun as Wang Yong, Wang Sai and Zhaiwang respectively, ruling Guanzhong and not letting Liu Bang enter Qin. When Liu Bangren was in Hanzhong, he took the advice of the famous counselor Sean and burned the plank road.
"Plank Road" is the ancient traffic artery of Nantong from Guanzhong, Hanzhong and Bashu across Qinling Mountains. It consists of the Qinling Ancient Road, Xiexie Road and Li Anyun Plank Road. It is 250 kilometers long and stands on cliffs and swamps. "Chencang" is the ancient name of Baoji, especially the Chencang ancient ferry on the north bank of Weihe River. The exit of Guanzhong plank road is about 70 kilometers away from Chencang's old capital.
In 206 BC, Han Xin, the general of Liu Bang, started military action with the strategy of "building a plank road and crossing a tight encirclement in secret". Han Xinxian sent Fan Kuai and Zhou Bo to pretend to repair the plank road burned by Liu Bangjin in Hanzhong, posing to send troops from the praise ramp. When Zhang Han heard the news, he immediately strengthened the oblique valley defense. Han Xin, however, came out from Mianxian County in the west with a great army, turned around and went north, entered Qinchuan along Chencang Trail, crossed the Weihe River at Chencang Ancient Ferry, and attacked the Big Three Pass. Zhang Han came to Chencangcheng and fought fiercely with Han Xin. At this time, Fan Kuai and Zhou Bo, who built the plank road in the Ming Dynasty, also walked out of Gu Jie and joined forces with Han Xin. Zhang Han was defeated and committed suicide, Sima Xin and Dong Kun surrendered successively, and Liu Bang decided to go to Sanqin. From then on, Guanzhong became the base for Liu Bang to defeat Xiang Yu and unify the world.
Today, Chencangyu, ten miles east of Baoji, is said to be Han Xin's hiding place after crossing the Weihe River. Nearby are the ruins of Mapo Spring and Dianjiangtai in Han Xin. Many Qin and Han weapons have been unearthed in this area.