Cao Cao’s army begins a southern campaign in the autumn of 208.
The Yangtze River in the area of Jing Province (covering present-day Hubei and Hunan provinces) is key to the success of this strategy.
If Cao Cao is to have any hope of reuniting the sundered Han empire, he has to achieve naval control of the middle Yangtze and command the strategic naval base at Jiangling as a means of access to the southern region.
Two warlords control the regions of the Yangtze that are key to Cao Cao's success: Liu Biao, Governor of Jing Province, controls the river west of the mouth of the Han, roughly encompassing the area around the city of Xiakou and all territory south of that region.
Sun Quan controls the river east of the Han and the southeastern territories abutting it.
A third ally, Liu Bei, is living in refuge with Liu Biao at the garrison in Fancheng (present-day Xiangyang), having fled from the northeast to Jing Province following a failed plot to assassinate Cao Cao and restore power to the imperial dynasty.
The initial stages of the campaign are an unqualified success for Cao Cao, as the command of Jing Province had been substantially weakened and the Jing armies exhausted by conflict with Sun Quan to the south.
Factions have arisen supporting either of Liu Biao's two sons in a struggle for succession.
The younger son prevails, and Liu Biao's dispossessed eldest son, Liu Qi, departs to assume a prefecture in Jiangxia (present-day Yunmeng County, Hubei) (de Crespigny 2004:241).
Liu Biao dies of illness only a few weeks later, while Cao Cao is advancing from the north and, under these circumstances, Liu Biao's younger son and successor, Liu Cong, quickly surrenders.
