Cao Cao's stratagem to divide Ma Chao and Han Sui is a military deception that converts a proposed winter truce into a crisis of confidence within Ma Chao’s coalition. Instead of relying only on direct force, Cao Cao and Jia Xu make ordinary acts of communication—conversation, a letter, and a relayed message—appear to confirm treachery. Ma Chao’s suspicion of Han Sui deepens until the alliance breaks, Han Sui changes sides, and Ma Chao is driven from the field with only a small group of loyal men beside him.

Background and Strategic Aim

After fierce fighting, including three inconclusive bouts between Ma Chao and Xu Chu, Cao Cao had been driven back to his fortified camp. Further sorties and counter-sorties allowed Cao Cao to establish a position on the west bank, putting Ma Chao under pressure from two directions. Several of Ma Chao’s officers, among them Han Sui, urged him to seek a truce through the winter. Emissaries carried that proposal to Cao Cao, who delayed his answer until the following day.

Jia Xu used the pause to recommend a different kind of attack: exploit the distrust between Ma Chao and Han Sui rather than treat them as a united force. Cao Cao accepted the proposal, agreed to a truce, and gave the appearance over the next several days of withdrawing. Ma Chao did not trust him and tried to watch Cao Cao’s positions closely, alternating with Han Sui so that each man could observe different sections of the opposing army. That caution, however, also made Ma Chao attentive to any sign that Han Sui might be communicating privately with their enemy.

A Meeting Made Suspicious

Cao Cao first approached Han Sui in a way that could be represented as harmless but was likely to attract attention. When Han Sui was opposite him, Cao rode out, identified himself as an ordinary man rather than a supernatural threat, and sent word that he wished to speak. The two leaders then met alone and talked for a couple of hours about earlier times, their families, and growing old. Their exchange was presented as innocuous; Cao Cao’s conspicuous laughter during it was the element Ma Chao would hear about and interpret.

Ma Chao asked Han Sui what had happened. Han Sui reassured him that the conversation had concerned only the past, but Ma Chao remained deeply suspicious. That reaction gave Cao Cao’s side an opening: the meeting itself had disclosed no betrayal, yet its secrecy and apparent familiarity could be made to look like evidence of one.

The Altered Letter and the Breaking Point

Jia Xu proposed sending Han Sui a letter with some words crossed out, others scratched out, and replacements written over them. The intended effect depended on Ma Chao seeing the changes and imagining that Han Sui had altered the letter to conceal its real message. When the letter arrived, Ma Chao demanded to inspect it and accused Han Sui of plotting to betray him. Han Sui denied the accusation and proposed a way to demonstrate his loyalty: he would speak with Cao Cao while Ma Chao waited for a signal to attack.

Cao Cao’s side then turned that plan into another apparent proof of conspiracy. As Han Sui was preparing to meet Cao Cao, Cao Hong rode up and loudly delivered a message that the prime minister wanted to reassure Han Sui after what he had said the previous night, so that there would be no mistakes. Ma Chao overheard the remark as intended and charged at Han Sui. Others intervened; Han Sui maintained his innocence, but Ma Chao rode away determined to take revenge. The message did not establish what the two leaders had discussed. Its force came from the suspicions already produced by the meeting and the marked letter.

Defection and Military Consequences

Han Sui’s position became untenable. His friends argued that Ma Chao would never trust him again, and Han Sui decided to go over to Cao Cao. He did so secretly while continuing to live in Ma Chao’s camp. Five other officers joined him in the betrayal, and they agreed to attack Ma Chao on a signal. The effort to make the alliance appear broken had now helped turn suspicion into an actual conspiracy.

Ma Chao learned of the arrangement before the attack could unfold as planned. Accompanied by loyal followers Pang De and Ma Dai, he entered Han Sui’s tent and found the conspirators together. A fight followed: Ma Chao cut down two of the men, while three escaped; Han Sui was pulled away to safety by attendants. Cao Cao’s troops then attacked, and Ma Chao’s force faced both an external assault and division within its own ranks.

Ma Chao took a small loyal force to defend the Wei bridge. Although he survived the arrows directed at him, repeated attempts to advance failed against the larger numbers facing him. He charged north, leaving his remaining men behind, but a crossbow shot killed his horse and Cao Cao’s troops closed in. Pang De and Ma Dai came to his rescue, surprised the pursuers, and enabled him to escape on another horse. Cao Cao offered a large reward for Ma Chao’s capture, but Ma Chao and a handful of followers, including Pang De and Ma Dai, reached sanctuary at Lintao.

Cao Cao rewarded Han Sui and the conspirators who survived, then returned with his army to Chang’an. The stratagem’s immediate result was not Ma Chao’s capture: it was the disintegration of his alliance, Han Sui’s defection, and Ma Chao’s forced retreat. The episode makes the cost of division concrete in the changed loyalties within the camp and in Ma Chao’s escape with only a few men still beside him.

Deception as a Weapon

The stratagem works through cumulative ambiguity rather than a single fabricated confession. Cao Cao’s private conversation with Han Sui is harmless in its described subject, but its visibility invites suspicion; the letter’s alterations have no stated message, but look like concealment; and Cao Hong’s remark acquires its meaning from Ma Chao’s prior doubts. Jia Xu’s plan exploits the gap between what Ma Chao can observe and what he can know, until each ambiguous sign seems to confirm the last.

The episode also distinguishes tactical success from the larger objective. Cao Cao’s deception breaks Ma Chao’s coalition and secures Han Sui and several officers, but Ma Chao escapes with help from Pang De and Ma Dai. The decisive achievement is therefore political as well as military: a force that had faced Cao Cao together is turned against itself, leaving Ma Chao isolated even before his flight makes that isolation visible. In the novel’s broader pattern of battles shaped by information, timing, and divided loyalties, the episode presents mistrust as a weapon that can prepare the way for force without guaranteeing the enemy commander’s capture.