Zhong Yao
In 211, Cao Cao sent Zhong Yao and Xiahou Yuan to lead an army to attack Zhang Lu in Hanzhong Commandery. They were due to pass through the Guanzhong region along the way. Ma Chao suspected that Cao Cao was planning to attack him, so he contacted Han Sui to form an alliance. He told Han Sui, "Previously, Zhong Yao ordered me to harm you. Now, I know that the people from Guandong (east of Tong Pass) cannot be trusted. Now, I abandon my father, and I'm willing to acknowledge you as my father. You should also abandon your son, and treat me like your son." Han Sui's subordinate, Yan Xing, urged his superior not to cooperate with Ma Chao but Han still agreed to the alliance. Ma Chao also contacted Yang Qiu, Li Kan (李堪), Cheng Yi (成宜), Hou Xuan (侯選), Cheng Yin (程銀), Zhang Heng (張橫), Liang Xing (梁興), Ma Wan (馬玩) and others, and they formed a 100,000 strong coalition army to attack Tong Pass (present-day Tongguan County, Shaanxi). Liu Zhang, the governor of Yi Province (covering present-day Sichuan and Chongqing), wanted to marry his daughter to Ma Chao to build ties with Ma, but Wang Shang (王商), a commandery administrator under Liu Zhang, opposed the idea and said that Ma Chao was courageous but inhumane and untrustworthy.