Cao Cao, in preparation for a campaign far to the north of the imperial heartland, has put Dong Zhao in charge of digging two canals, the Pinglu Trench ("Pacify-the-Caitiffs Trench") and the Quanzhou Trench, from the autumn of 206 to spring of 207 so he can use these waterways to ship supplies to the north.

While these works are under way, some generals try to dissuade Cao Cao from campaigning so far to the north in case of an attack from the south, fearing that Liu Bei would certainly persuade Liu Biao, the Governor of Jing Province, to raid Xu City, Cao’s capital.

However, Cao Cao's strategist Guo Jia urges a swift attack, opining that the Wuhuan, being so far away from the Chinese heartland, are deluded by a false sense of security and can be defeated and destroyed in a quick attack.

Otherwise, the Yuan brothers and the Wuhuan would cause trouble, and the newly settled northern provinces would be lost.

Further, Liu Biao would then not be persuaded by Liu Bei, who he does not trust in any case, to launch an attack on Xu City.

Cao Cao agrees with Guo Jia's analysis, and in the summer of 207, Cao personally marches his army to Yijing (present-day Yi County, Hebei) and makes the city his base camp for the campaign.

From here, …