During the Three Kingdoms period, Yang Xiu served as a registrar under the warlord Cao Cao and also acted as an advisor to his son Cao Zhi. Exceptionally clever yet arrogant, Yang Xiu constantly flaunted his brilliance.
Cao Cao once tested his sons Cao Pi and Cao Zhi by ordering them to leave Ye City, secretly instructing the gatekeepers to block their way. Cao Pi failed to get out. Cao Zhi secretly sought advice from Yang Xiu, who told him, "If the guards won't let you pass by royal decree, then kill them—you carry the prince's authority." Following this plan, Cao Zhi forced his way out. When Cao Cao learned Yang Xiu had coached him, he was furious and grew to despise Yang Xiu.
Cao Cao initially favored his younger son Cao Zhi and planned to make him crown prince. However, Cao Zhi was timid and aloof by nature, lacking the cunning of his elder brother Cao Pi. Gradually, Cao Cao shifted his support to Cao Pi, sidelining Cao Zhi, and eventually named Cao Pi as heir. He then began to suppress Cao Zhi and his associates. Yang Xiu, a brilliant and outspoken talent, was also a nephew of Yuan Shu. Fearing that Cao Pi would struggle to control Yang Xiu in the future, Cao Cao schemed relentlessly to find an excuse to kill him, eliminating this potential threat.
During the battle for Hanzhong, Cao Cao found himself in a dilemma: his forces were on the defensive at Xie Valley, too weak to attack yet fearful of holding their ground. While hesitating, someone served him chicken soup. Spotting the chicken ribs in the bowl, he was struck by inspiration. Just then, Xiahou Dun entered the tent to request the night watchword, and Cao Cao blurted out, "Chicken ribs, chicken ribs." The order was passed down, leaving everyone puzzled. Yang Xiu, however, told his men to prepare for retreat, explaining, "Chicken ribs—gnawing them yields no flavor, yet tossing them feels wasteful. From this watchword, the Duke has likely decided to withdraw." When Cao Cao indeed retreated, he realized Yang Xiu had seen through his mind. Furious and alarmed, Cao Cao charged Yang Xiu with "spreading lies to disrupt morale" and had him executed, finally eliminating a source of worry. Source: *Chronicles of the Three Kingdoms*, "Biography of Cao Cao"
After executing Yang Xiu, Cao Cao wrote a letter to Yang Xiu's father, Yang Biao, and sent some imperial gifts from the emperor as a gesture of consolation. The letter read: "I established military orders that the chief clerk should follow, but your son, relying on your family's prominent influence, often disagreed with me. I sought to correct him, yet he harbored resentment. I hoped he would reform, but instead he grew more reckless. If I had tolerated him further, he might have brought disaster upon your entire household, so I ordered his execution. Thinking of your father-son bond, I too feel sorrow, yet perhaps this is not without its fortune."
After learning of his son's execution, Yang Biao was consumed by grief, growing thinner by the day. Yet, with Cao Cao holding immense power, he dared not speak his pain, burying it deep within. One day, Cao Cao noticed his frailty and asked, "Why have you become so gaunt?" Yang Biao replied, "During Emperor Wu of Han's reign, Jin Midi had the foresight to kill his own unruly son before disaster struck. I am ashamed that I lack such wisdom, and instead harbor a love for my son like an old cow licking its calf." His raw sorrow was laid bare, and even Cao Cao was moved. Source: *Chronicles of the Three Kingdoms*, "Biography of Yang Biao"
Later, the idiom "The Love of Licking the Calf" came to be used as a metaphor for parental affection.
Source: *Book of the Later Han*, "Biography of Yang Biao"
Meaning of the Idiom: Later, the Chinese idiom "舐犊之爱" came to describe how parental affection is deep and selfless, like a cow licking its calf.