At the battle of Guandu, Yuan Shao’s adviser Xu You went over to Cao Cao. The Records of the Three Kingdoms says he “was greedy for wealth, and Yuan Shao could not satisfy him.” He urged Cao Cao to attack Chunyu Qiong and his troops. Cao Cao did, and Yuan Shao’s army collapsed.
A commentary quotes an older account of the meeting. Cao Cao ran out barefoot to greet Xu You. Xu You asked how much grain was left. “Enough for a year,” said Cao Cao. “Not so. Say it again.” “Half a year.” “Why do you not tell the truth?” At last Cao Cao admitted that there was enough for one month. Only then did Xu You tell him that Yuan Shao’s supply wagons stood at Gushi and Wuchao, poorly guarded.