Guo Jia, styled Fengxiao (奉孝), was a strategist and advisor to the powerful warlord Cao Cao during the late Eastern Han Dynasty and Three Kingdoms Period in ancient China. During his eleven years of service, Guo Jia's brilliance greatly aided Cao Cao in his victories over rival warlords Lü Bu and Yuan Shao, as well as chief of the Wuhuan tribe Ta Dun. As a result of this, he was one of the most trusted and favored subjects of Cao Cao. Wikipedia
The definitive Wikipedia entry for Guo Jia. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Guo_Jia
