During the reign of King Xuan of Zhou, to prevent invasions by the southeastern Yi tribes, a large group of fiefs belonging to the same clan was established in the southeastern region of the Central Plains. His younger brother, Ji You, was enfeoffed at Zheng, becoming Duke Huan of Zheng. During the reign of King You of Zhou, Duke Huan of Zheng served as a high minister. Later, when the Western Rong attacked Haojing, Duke Huan of Zheng escorted King You and was killed in battle. After his death, his son succeeded him, becoming Duke Wu of Zheng. Duke Wu of Zheng rendered great service in quelling the Quanrong rebellion, welcoming King Ping of Zhou to the throne, and escorting him during the eastward relocation of the capital, for which he was appointed as a high minister of Zhou. After ascending the throne, Duke Wu focused his efforts on strengthening the state, annexing the states of Kuai (present-day southeast of Mi County, Henan) and Eastern Guo (present-day northeast of Xingyang, Henan), and establishing passes and fortifications. From then on, the state of Zheng gradually grew powerful.
Duke Wu of Zheng's wife was Wu Jiang, the daughter of the Marquis of Shen. In the fourteenth year of Duke Wu of Zheng's reign (757 BCE), Wu Jiang had a difficult childbirth that frightened her, so she named the child Wusheng (literally "born in fright"). Because Wusheng had scared his mother during birth, he was never favored by Wu Jiang from childhood. Three years later, Wu Jiang gave birth again, this time smoothly, to a son named Shuduan, whom she deeply loved.
Wu Jiang was determined to have her younger son inherit the throne, often praising him before Duke Wu of Zheng, claiming he was several times more intelligent and brave than Wusheng, and urging Duke Wu to appoint the younger son as heir. However, Duke Wu did not follow Wu Jiang's advice and insisted on adhering to ritual law by making Wusheng the crown prince. Shuduan was only granted the fief of Gongcheng, and people called him Gongshuduan. In 744 BCE, Duke Wu died of illness, and Wusheng succeeded to the throne—he was Duke Zhuang of Zheng.
Wu Jiang, seeing that her younger son had no power, asked Duke Zhuang to grant the territory of Zhi (present-day Sishui Town, Xingyang, Henan) to Shusegment as his fief. Duke Zhuang told his mother that the terrain of Zhi was strategically important, a military stronghold crucial to the state's security, and could not be enfeoffed. But Wu Jiang was not deterred and instead demanded that Duke Zhuang grant the city of Jing to Duan. Jing was a major city of the Zheng State, with high walls, a large population, abundant resources, and great wealth. Minister Ji Zhong admonished, "Jing is larger than the capital, and it is well known that the Lady dotes on Duan. If you grant Jing to him, he may become arrogant due to favoritism and cause turmoil in the future." However, Duke Zhuang felt that he had already refused his mother once and could not do so again, so he ultimately granted Jing to Shusegment.
After Shuduan obtained the capital city of Jing, Jiangshi was still not satisfied and kept thinking about making her younger son replace Wusheng as the ruler of the Zheng State. She instructed Gongshuduan to actively recruit soldiers, gather horses, and stockpile provisions in Jing, making thorough preparations to usurp the throne. She herself would look for an opportunity to collaborate from within, helping him attack the capital and replace Wusheng as the ruler.
With his mother's backing, Gongshu Duan took his trusted followers to the capital city of Jing, where he styled himself "Elder of the Capital." Relying on his mother's support, he focused entirely on strengthening his military power and expanding his influence. On one hand, he stockpiled grain and intensified military training; on the other, he used hunting as a pretext to seize territories such as Linyan.
The common people within and outside the capital were already buzzing with discussions about Taishu Duan's actions. Duke Zhuang was also very clear about what he had done and was well aware that his mother wanted Shuduan to succeed the throne. However, he let things take their course and took no action.
The senior minister Lü admonished, "If the walls of a fief exceed three hundred zhang in height, they pose a threat to the state's security. Therefore, the rites of the former kings decree that a large fief must not exceed one-third of the capital; a medium one, one-fifth; and a small one, one-ninth. Now, the city of Jing is larger than the capital itself—how can you stand by and ignore this?" Duke Zhuang merely replied, "This is my mother's wish; what can I do?" Lü said, "Her demands have no end. Even weeds are hard to eradicate once they spread, and he is your own brother. Better to curb his growth now while you still can by assigning him a place." Duke Zhuang responded, "Shu Duan is my brother by the same mother—how could I harm our fraternal bond over land?"
Duke Zhuang's forbearance made Taishu Duan believe he was weak and easily bullied, and with their mother's support, Taishu Duan grew even more emboldened, his ambition to usurp power and seize the throne swelling further. Before long, Taishu Duan forcibly issued orders to the western and northern border regions, where officials, fearing him, had no choice but to comply; he then annexed two small towns near the capital of Jingyi into his own domain.
Senior Minister Lü said to Duke Zhuang, "There cannot be two suns in the sky, nor two rulers in a state. I wonder what Your Highness truly intends—will you yield the throne to the Grand Uncle? If so, your servant will go and serve him; if not, I urge you to make a decisive move to eliminate him, lest the people become divided in their loyalties." Duke Zhuang replied, "Let us wait and see. One who commits many unjust acts will surely bring about their own downfall!"
Minister Jizhai said to Lü: "The ruler is exceptionally wise and will naturally not neglect the state and its altars, but as the sovereign of a nation, he cannot reveal everything in his heart."
Prince Lü said no more, but that evening he went to see Duke Zhuang again. The Duke said, "Although Shuseg is arrogant, he has not yet rebelled. If we deal with him too early, our mother will surely interfere, and then people will say I am unfilial to her and intolerant of my own brother. For now, let him indulge his arrogance. When he truly rebels, punishing him will be more justified, and even our mother will have nothing to say." Lü replied, "Since we know he will rebel sooner or later, why not test him?" So he devised a plan for the Duke.
At the next morning's court, Duke Zhuang falsely announced that he would go to the Zhou royal court to assist in governance for a long time, and that all matters of Zheng State would be supervised by Minister Zhai Zu.
When Lady Jiang learned of this, she felt that the state was vulnerable and saw it as a perfect opportunity to seize power, so she immediately wrote a secret letter to Taishu Duan, agreeing to launch an uprising on the fifth day of the fifth month. However, Gongzi Lü had long since sent people to track her, and they intercepted the letter. After reading it, Duke Zhuang resealed it and had someone else deliver it to Taishu Duan. Upon receiving the letter, Taishu Duan replied that he would act as planned and attack the capital of Zheng on the fifth day of the fifth month. Of course, the reply fell into Duke Zhuang's hands, and after reading it, he said, "It's time to take action!"
Duke Zhuang first led part of his army to occupy Linyan. Prince Lü commanded two hundred chariots and set up an ambush around the capital city of Jing, while also sending men disguised as merchants to infiltrate the city. On the fifth day of the fifth month, Taishu Duan led out all the troops he had painstakingly trained from Jing. At that moment, Duke Zhuang's soldiers, who had previously infiltrated the city, immediately seized the city gates and set off a fire as a signal. Prince Lü then occupied Jing without any effort. After taking Jing, Prince Lü posted a notice promising not to disturb the common people, reassuring them. The people, already dissatisfied with Taishu Duan's actions, now saw Duke Zhuang's benevolence and became even more supportive of him.
Taishu Duan encountered Lü's ambush midway, his army was utterly routed, and now his base had been seized, with Linyan also captured by Duke Zhuang, forcing him to flee with his troops to Yan. Taishu Duan's soldiers were mostly from the city of Jing, and upon learning that Jing had fallen and that Duke Zhuang's army had not harmed the common people, they lost all will to follow Taishu Duan in his escape; within a few days, most of his soldiers had deserted. Soon, Taishu Duan's army had dwindled to almost nothing. Duke Zhuang pressed his advantage, pursued the remnants, and led his forces to Yan to continue the campaign, where Taishu Duan later committed suicide by cutting his own throat.
Duke Zhuang was extremely angry with his mother. He found the letter that Jiang had written to Shuduan and ordered Jizu to deliver both this letter and Taishuduan's reply to Jiang. He then relocated Jiang to Yingdi and swore an oath: "Until we meet again in the Yellow Springs, we shall never see each other."
Upon seeing the letter and learning that the plot was exposed and Shuduan had died, Jiang felt deeply ashamed. Unable to face Duke Zhuang, she immediately left the capital and went to Yingdi.
The rebellion's turmoil thus subsided. After some time, Duke Zhuang's resentment toward his mother faded, and he felt sorrowful thinking that she was, after all, his own mother, yet he could not enjoy her company or share family bonds. However, though he missed her, he was bound by his own oath and could not meet with her. Later, he ordered a high terrace built, and whenever he climbed it to gaze toward the direction of Ying, it signified his longing for his mother; people thus named it the "Mother-Gazing Terrace" (located south of the Wei River in present-day Xinzheng, Zhengzhou, Henan Province).
The official governing the Ying region, Ying Kaoshu, was renowned for his filial piety and fraternal devotion. Upon learning of this matter, he wished to help reconcile the mother and son. He therefore sought an audience with Duke Zhuang and, using the opportunity to present a gift, offered a suggestion: "It is not necessary to die before reaching the Yellow Springs. Have someone dig an underground passage, and meet your mother where the spring water emerges. This way, you can see your mother without breaking your oath."
Upon hearing this, Duke Zhuang was extremely delighted and immediately appointed Ying Kaoshu to handle the matter. Soon, Ying Kaoshu had a tunnel dug, and then escorted Lady Jiang into the tunnel to meet with Duke Zhuang. Lady Jiang was deeply ashamed and greatly moved that her son could set aside past grievances. The rift between mother and son instantly dissolved. Later, Duke Zhuang sang with emotion: "Within the great tunnel, the joy is harmonious and warm."