When the Yellow Turban Rebellion broke out in the 180s, a county magistrate, Wang Du, burnt down the food stored in the warehouse and instigated his subordinates to seize the city.
The county prefect escaped the city and went into hiding, while the town residents took their families eastward and camped beside a mountain.
After receiving intelligence from his spies that Wang Du had moved out and camped 1.3 to 1.6 miles away from the city, Cheng Yu reported to and told a local parvenu, Xue Fang, that Wang Du must not have the ability to control the situation, so they should retrieve the prefect and reoccupy the city.
He then plotted with Xue Fang, and secretly sent several cavalry holding streamers to the hilltop, where they rode down toward the civilians.
Xue Fang and his men then screamed upon seeing the riders, making the commoners mistake them for Yellow Turban rebels.
Seeing the inhabitants had come back, Wang Du launched an attack, but was foiled by Cheng Yu's defences.
Cheng Yu then led a sudden attack when Wang Du was packing, dealing him a major blow which enabled the survival of Dong'e County.
Liu Dai then sought advice from Cheng Yu, who told the former that asking for help from Gongsun Zan was like requesting someone to save a drowning child from afar.
[8] He further analysed that Gongsun Zan, who had recently gained a minor military victory over Yuan Shao, would eventually lose to the latter.
Just as Cheng Yu had predicted, Gongsun Zan soon suffered a heavy defeat by Yuan Shao before his cavalry could even join the battle.
When Lü Bu claimed his rule over Yan Province, many people gave up resistance and joined him; only Juancheng, Dong'e and Fan counties did not yield.
Cheng Yu sought a meeting with the prefect and managed to persuade him to reject and kill Si Yi.
When he arrived at Dong'e County, Xue Ti (薛悌) and Zao Zhi (棗祗) had already set up defences around the area, so Cheng Yu split his cavalry force out to take control of Cangting ford to block the advances of Lü Bu's strategist, Chen Gong.
Once, the supply line was blocked by Gao Fan, the Administrator of Wei Commandery, who capitalised on the geographic advantage.
However, Li Dian reasoned with Cheng Yu that Gao Fan could be defeated because he was lightly guarded with a small army.
The majority believed that Sun Quan would surely kill Liu Bei and submit to Cao Cao, but Cheng Yu correctly analysed that Sun Quan would support Liu Bei to fight a desperate war.
When Cao Pi sent a general to subdue the revolt, several thousand rebels offered to surrender after being besieged.
To execute those who surrender after being besieged could intimidate other potential enemies, and encouraged early submissions; subsequently, we did not need to lay siege every time.
"[15] The feckless audience simply ignored Cheng Yu's rationale, and vindicated their choice by claiming that they had the autonomy over military issues and that it was not necessary to report every single provision.
After the exodus, Cao Pi specifically consulted Cheng Yu to see if he held any thought back in the discussion, wherein Cheng Yu replied, "The reason why Commandants and Commanders were given autonomic power is because frontline military issues are so imminent that decisions must be made immediately.
Cheng Yu remained as a commoner and seldom left his home until Cao Pi usurped the throne from Emperor Xian in late 220.
Cheng Yu was re-instituted as the Minister of the Guards[d] and earned a tax revenue from a marquisate composed of 800 taxable households.
[e] Since Cao Pi intended to make Cheng Yu one of the Three Ducal Ministers when he became emperor in late 220, a discussion was made in regard to the issue.
He was given the posthumous title "Marquis Su" for his inviolable reverence (See Xing Zhen's case in the following section).
It was recorded that Cheng Yu would have the abducted cut into pieces to mix with rice, so the soldiers would enjoy their prized meals.