After the collapse of Su Qin’s Vertical Alliance (Hezong), a new threat emerged to Qin’s ambition: the alliance between Qi and Chu, the two most powerful eastern states. United, they could block Qin’s path to unification.
In July 219 CE, Guan Yu launched the Battle of Xiangfan, attacking Cao Cao’s forces. To prevent the front line from collapsing, he transferred troops from Jingzhou to reinforce the front, leaving Jingzhou’s defenses depleted. Taking advantage of this opportunity, Lü Meng of Eastern Wu led his army across the Yangtze River and launched…