Editing Three Kingdoms (section)

====North China Plain====
Cao Cao, whose zone of control was the precursor to the state of Cao Wei, had raised an army in 189. In several strategic movements and battles, he controlled Yan Province and defeated several factions of the Yellow Turban rebels. This earned him the aid of other local militaries controlled by [[Zhang Miao (politician)|Zhang Miao]] and [[Chen Gong]], who joined his cause to create his first sizeable army. He continued the effort and absorbed approximately 300,000 Yellow Turban rebels into his army as well as a number of clan-based military groups from the eastern part of Qing Province. Since 192, he developed military agricultural colonies (''[[tuntian]]'') to support his army. Although the system imposed a heavy tax on hired civilian farmers (40% to 60% of agricultural production), the farmers were more than pleased to be able to work with relative stability and professional military protection in a time of chaos. This was later said to be his second important policy for success.

In 200, [[Dong Cheng (Han dynasty)|Dong Cheng]], an imperial relative, received a secret edict from Emperor Xian to assassinate Cao Cao. He collaborated with Liu Bei on this effort, but Cao Cao soon found out about the plot and had Dong Cheng and his conspirators executed, with only Liu Bei surviving and fleeing to join Yuan Shao in the north. After settling the nearby provinces, including a rebellion led by former Yellow Turbans, and internal affairs with the court, Cao Cao turned his attention north to Yuan Shao, who himself had eliminated his northern rival Gongsun Zan that same year. Yuan Shao, himself of higher nobility than Cao Cao, amassed a large army and camped along the northern bank of the Yellow River. In the summer of 200, after months of preparations, the armies of Cao Cao and Yuan Shao clashed at the [[Battle of Guandu]] (near present-day Kaifeng). Cao Cao's army was heavily outnumbered by Yuan Shao. Due to a raid in Yuan's supply train, Yuan's army fell into disorder as they fled back north.{{sfn|de Crespigny|1991|p=4}}

Cao Cao took advantage of Yuan Shao's death in 202, which resulted in division among his sons, and advanced to the north. In 204, after the [[Battle of Ye]], Cao Cao captured the city of [[Ye, China|Ye]]. By the end of 207, after a victorious campaign beyond the frontier against the [[Wuhuan]] culminating in the [[Battle of White Wolf Mountain]], Cao Cao achieved complete dominance of the [[North China Plain]]. He now controlled China's heartland, including Yuan Shao's former territory, and half of the Chinese population.{{sfn|de Crespigny|1991|pp=4, 6}}