Duke Zhuang of Zheng (Chinese: 鄭莊公; 757–701 BC) was the third ruler of the State of Zheng during the Spring and Autumn period in ancient China. His ancestral name was Ji (姬), given name Wusheng (寤生), which means "difficult birth" with breech presentation. In 743 BC, he became the duke of Zheng, and later defeated his brother Gongshu Duan, who had led a rebellion against him. Duke Zhuang led military campaigns in the name of the Zhou king against the Rong people and other Zhou states. He was considered by later scholars, Machiavellian towards governance.
Born as the first of two sons and groomed for the throne, Zheng's mother nevertheless preferred her second son, the reason being that she suffered through an extraordinarily painful time when giving birth to Zheng. When Duke Zheng ascended to the dukedom over the violent objections of his mother, she began plotting to get Gongshu Duan into power. First she asked Zheng to give Gongshu Duan the city of Duan as a fiefdom. Duan, at that time, was the second largest city in Zheng, and was a very important fortress indeed. Zheng was extremely reluctant to give away that piece of land, and indeed his courtiers begged him to reject the proposal, but out of courtesy for his mother he agreed.
Seeing that her plan was going well, Zheng's mother urged Duan to build walls, stockpile arms and recruit mercenaries to the rebel cause. Soon news of all this began to reach the capital, and it was clear to everybody what was going to happen. Zheng's ministers urgently reported the news to Zheng, urging him to retake Duan from Gongshu before it was too late. However, Zheng dismissed these proposals, stating that he found no fault in Gongshu Duan, and besides, it could not be proved that he was plotting a coup, instead of just merely reinforcing the border. Besides, he said that Gongshu Duan was his brother, and he could not take up arms against him.
Soon King Zheng had left the dukedom to Luoyang for some diplomatic matters; his mother soon wrote a letter to Duan, ordering him to revolt now and she would open the gates of the capital for him. So Gongshu Duan revolted against Duke Zheng, and not long after he was under the capital walls. It seemed as if Zheng was finished.
However word then came that Duan had fallen to the forces of Zheng, much to everyone's surprise. Duke Zheng already knew that a revolt was imminent, so he set up a trap; which both his mother and brother fell into. Seeing his demoralized forces melt away and with nowhere to run, Gongshu Duan committed suicide. Upon hearing this, Zheng rushed to see his brother's corpse; weeping greatly, he said to him, "Gongshu Duan, you knew that your older brother would always forgive you; why has it come to this?"