In 200 CE, war broke out between Cao Cao and the northern warlord Yuan Shao. At the Battle of Boma, Xun You suggested that Cao Cao use a diversionary tactic to eliminate Yuan Shao's general Yan Liang; the battle ended with victory for Cao Cao and Yan Liang's death at the hands of Guan Yu. After the victory at Boma, Cao Cao and his forces headed west with their baggage train along the south banks of the Yellow River. Yuan Shao sent his troops across the river to raid the baggage train and they encountered Cao Cao. Cao Cao's subordinates were shocked and they asked him to head back to protect his camp. Xun You said, "This is an opportunity to capture the enemy! Why should we retreat?" Cao Cao looked at Xun You and laughed. He then ordered his troops to use their baggage as bait to lure Yuan Shao's forces into a trap. At the Battle of Yan Ford, when Yuan Shao's soldiers were scrambling for the baggage, Cao Cao sent his infantry and cavalry forces to attack them and scored a major victory; Yuan Shao's general Wen Chou was killed in action. Cao Cao then retreated to Guandu (官渡; northeast of present-day Zhongmu County, Henan); Yuan Shao laid siege to Guandu. As both sides reached a stalemate at Guandu and Cao Cao's forces ran out of supplies, Xun You advised Cao Cao, "Yuan Shao's supplies will be reaching in one day. Han Xun (韓𦳣), the officer leading the convoy, tends to underestimate the enemy. He can be easily defeated." Xun You also recommended Cao Cao's general Xu Huang to lead the attack on Han Xun. Cao Cao sent Xu Huang and Shi Huan () to raid Han Xun's convoy and they burnt the supplies. Later, Yuan Shao's adviser Xu You defected to Cao Cao's side and urged Cao to attack Yuan's supply depot at Wuchao (烏巢; southeast of present-day Yanjin County, Henan), which was guarded by Chunyu Qiong. While Cao Cao's other subordinates were suspicious about Xu You, only Xun You and Jia Xu advised Cao to heed Xu You's suggestion. Cao Cao then ordered Xun You and Cao Hong to remain behind to guard his main camp, while he personally led his forces to attack Wuchao and succeeded in destroying Yuan Shao's supplies and killed Chunyu Qiong in battle. As the tide turned against Yuan Shao,