During the late Eastern Han Dynasty, the warlord Cao Cao, commanding a formidable army and controlling the imperial court, decided to eliminate his rivals by first crushing the weaker Liu Bei, who had just arrived in Xuzhou with a small, unstable force. Cao Cao's army swiftly defeated Liu Bei, and in the chaos, Liu Bei was separated from his sworn brothers Guan Yu and Zhang Fei, fleeing alone on horseback to seek refuge with Yuan Shao, while Guan Yu held his ground at Xiapi, protecting Liu Bei's two wives.
Cao Cao had long admired Guan Yu's martial prowess and noble character, hoping to recruit him. He devised a plan: first, he sent agents into Xiapi to serve as insiders; the next day, he led his army to the city gates and challenged Guan Yu to battle. Guan Yu rode out to fight, but several of Cao Cao's generals took turns engaging him, refusing to let him break free. Meanwhile, the insiders inside the city opened the gates, and Xiapi fell to Cao Cao's forces. Guan Yu realized he had been tricked, and with his two sisters-in-law (Liu Bei's wives) now in Cao Cao's hands, he had no choice but to surrender temporarily.
Guan Yu brought his two sisters-in-law to Cao Cao's camp in Xuchang. To win Guan Yu over, Cao Cao bestowed upon him the title of "Marquis of Hanshou Pavilion," along with silks, brocades, gold, silver vessels, and ten beautiful women. Without even a glance, Guan Yu handed everything over to his sisters-in-law to handle.
One day, Cao Cao noticed that Guan Yu's battle robe was worn out and presented him with a new one
Cao Cao asked, "General Guan, why do you live so frugally?" Guan Yu replied, "It's not frugality—this old robe was a gift from my elder brother. Wearing it feels like seeing him. How could I forget his gift just because of your new one?" Cao Cao fell silent for a long moment. Another time, Cao Cao hosted a feast for Guan Yu. After the banquet, seeing Guan Yu's horse looking thin and weak, Cao Cao remarked, "How can a great general lack a fine steed?"
Cao Cao immediately presented Guan Yu with a magnificent Red Hare steed. Overjoyed, Guan Yu knelt and bowed in gratitude.
Cao Cao asked curiously, "I gave you gold, silver, and beautiful women, yet you never thanked me. Why bow for a single horse?" Guan Yu replied, "I know this horse can travel a thousand li a day. With it, if I learn of my elder brother's whereabouts, no matter how far, I can reach him in one day."
Cao Cao realized that Guan Yu, though staying in Cao's camp, was constantly thinking of Liu Bei, the imperial uncle of Han.
Later, when Guan Yu learned that Liu Bei was with Yuan Shao in Hebei, he wrote Cao Cao a farewell letter that very night, thanking him for his hospitality. He hung the golden seal of "Marquis of Hanshou" on a beam, sealed all the bestowed gold, silver, and beauties untouched in a room, then took his attendants, escorted the two sisters-in-law's carriage, and departed through the northern gate of Xuchang, heading for Hebei. Along the way, he passed five passes and slew six generals, finally returning to Liu Bei's side.
Later, people used the phrase "Body in Cao Camp, Heart in Han" to describe those who remain loyal to their original master despite being in a different situation. It also refers to being physically present in one place while one's mind is elsewhere, lacking focus.
Source: *Romance of the Three Kingdoms*
Meaning of the Idiom: Later, the Chinese idiom "身在曹营心在汉" came to describe those who remain loyal to their original master despite being in a different situation and being physically present in one place while one's mind is elsewhere lacking focus.