Gao Gan
Although Gao Gan surrendered to Cao Cao, he was only pretending to do so. In 205, when Cao Cao was away on a campaign against Yuan Shang and the Wuhuan tribes, Gao Gan seized the opportunity to start a rebellion in Bing Province. He took the Administrator of Shangdang Commandery (上黨郡; a commandery in Bing Province) hostage and fortified his defences at Hu Pass (壺關; west of present-day Lucheng, Shanxi). Cao Cao's forces, led by Li Dian and Yue Jin, attacked Gao Gan at Hu Pass but could not overcome him even after some months of siege.