The Ba River's left and right branches, known in later ages as the Chanba, merged into the Ba River before flowing into the Wei River. This was the basic geography east of Chang'an.
Huan Wen and his main force were stationed between the two branches, with his central army forward and Huan Chong slightly behind. The place Liu Cheng had been ordered to go was actually east of the Ba River, across its right branch. In theory, this territory was already under Huan Wen's control.
The actual ruler of the area near the Ba River, in and around Ba County, was a powerful Xiongnu magnate who had already accepted an appointment from Huan Wen-Huyan Du.
It made sense. As a Xiongnu, he was bound to be the target of the Di people's might when they dispensed both favors and intimidation. And with Huan Wen's great army now cutting off half the approaches to Ba County, Huyan Du had no reason not to draw closer to him.
Thus, he had been among the first to raise the banner of rebellion against the Di regime after the Battle of Lantian, and the very first to send an envoy to Huan Wen.
In a sense, he was probably the only great Guanzhong magnate over whom Huan Wen could currently exert any real influence.
And he truly was a great magnate. However he had acquired them, he directly controlled over ten thousand adult males in and around Ba City. Counting everyone within Ba County's sphere of influence, his population probably reached twenty or thirty thousand. He could muster at least three or four thousand men-the best possible guides, laborers, and expendable manpower for war.
One of Liu Acheng's tasks on this trip, perhaps even his main task, was to win this man over or