Jia Xu

After Dong Zhuo's death, Jia Xu advised his subordinates Li Jue and Guo Si to gather their troops and attack Chang'an rather than disbanding. This led to the capture of the capital and the restoration of their power, though it plunged the region into further chaos.

Jia Xu left Zhang Xiu's service and joined Cao Cao, bringing with him strategic advice. Cao Cao welcomed him and later relied on his counsel for major decisions.

When Cao Cao hesitated to engage Yuan Shao due to lack of supplies, Jia Xu argued that Cao Cao's strategic acumen and the morale of his troops outweighed Yuan Shao's numerical advantage. Cao Cao followed the advice and won the Battle of Guandu.

After Cao Cao's defeat at Red Cliffs, Jia Xu advised against a hasty second invasion of Jiangdong, arguing that Cao Cao should consolidate his gains first. Cao Cao did not follow this advice and suffered further setbacks.

Jia Xu recommended that Cao Cao launch a campaign against Zhang Lu in Hanzhong using a mountain route. The campaign succeeded, and Cao Cao gained control of Hanzhong.