Badong Commandery (巴東郡; covering parts of present-day Chongqing) was a territory held by Shu Han that was located near the border of its ally, Eastern Wu.
Yan Yu's deputy, Luo Xian,[1] remained behind with only 2,000 troops to guard Yong'an (永安; present-day Fengjie County, Chongqing), the capital of Badong.
[7][8] Around March 264, the Wu general, Bu Xie, led troops from Xiling (西陵; present-day Yichang, Hubei) to attack Yong'an but encountered strong resistance from Luo Xian and his men.
As the Wu forces rained arrows on his position, Luo Xian ordered his subordinate, Yang Zong (楊宗), to break out of the siege and seek help from the Wei general, Chen Qian.
[11][12] After Chen Qian relayed Luo Xian's call for help to Sima Zhao, the Wei regent ordered the general, Hu Lie, to lead 20,000 troops from Jing Province to divert Wu forces from Yong'an by attacking Xiling.