Time was when Duke Wu of Zheng married Lady Wujiang from Shen and later they gave birth to Duke Zhuang and another son Gongsuduan. Zhuang was difficultly delivered; his mother Wujiang was startled and so named him Wusheng; literally his feet, instead of his head, came out first from his mothers womb. Therefore, Wujiang disliked him very much and then loved his brother Gongsuduan much better, trying many times to persuade Duke Wu into appointing her second son as the heir. But the duke refused.
Later on, Duke Zhuang acceded to the throne. his mother Wujiang asked him to offer his brother Gongsuduan a fief at Zhi. The duke said, "Zhi is a dangerous place and formerly Duke Guo died there. I shall grant my brother anywhere else as you wish." So Wujiang asked for Jing, and the duke agreed and let Gongsuduan be there with the title of Grand Marquis of Jing. A senior official Zhaizhong exhorted the duke not to make such a decision, "If the surrounding wall of a fief exceeds three hundred squre Zhi, that will imperil our state. According to the established rule, a metropolitan can only be as large as one third of the capital in the measure of area; middle-sized city, one fifth; and small-sized town, one nineth. The measure of Jing breaks the rule, which is not allowed. It will be a latent threat to Your Highness." The duke replied, "That is my mother Wujiang who wants to do it, what can I do to evade the threat?" Zhaizhong observes, "Your mother Wujiang is insatiable. Your Highness had better address yourself to the issue in time, and do not let the root of trouble grow; otherwise, it will be very hard to tackle with. The widespread weeds are difficult to eradicate if you do not snap them in the incipient stage, let alone your spoiled brother!" Duke Zhuang said, "Unjust is doomed to destruction. You had better wait and see."
Later on, Marquis Gongsuduan annexed a fief of Zheng in the west frontier, and a rebel fief in the north. A pedigreed gentleman, Lu, advised, "There should not be two dukes coexisted within a state. What are Your Highness going to do about it? If you prepare to concede the whole state to the marquis, please allow me to serve him from now on. If you do otherwise, please get rid of him, and please convey a clear message to your subjects." The duke said, "No need of getting rid of him. He will suffer from his own actions." Ere long, Marquis Gongsuduan further occupied two other fiefs as his own, and expanded his territory to Linyan. Lu once more advised, "It is time Your Highness took action now. His expansion will soon get support from your subjects." Duke Zhuang said, " He shows no respect and obligation to his master, nor any affection to his own brother. The unlawful expansion will only lead him to final collapse."
Now Marquis Gongsuduan, reconstructing the walls, gathering more people, repairing weapons and armors, preparing carriages and soldiers, was going to launch a surprise attack on Zheng. Wujiang, his mother, would stood ready for assistance by opening the main capital gate. When Duke Zheng heard of the planned surprise attack, he said, "Now is the hour!" Then he dispatched 200 four-horsed carriages, led by Lu, as the punitive expedition to Jing. The people of Jing then rebelled against Marquis Gonsuduan, so he fleed to Yan, and Duke Zheng continued to pursuit. At last on 23th day of May, Marquis Gongsuduan further fleed to Gong.
Book of Spring and Autumn comments, "Why do I say Earl Zheng "conquered" Gongsuduan at Yan? Because Gongsuduan did not behave himself as a younger brother, but acted himself as the eaqul noble as another duke, so I use the word: conquer. Why do I say Earl of Zheng instead of Duke of Zhang? Because I insinuate that he did not teach his younger brother well in the first place, and then out of his own will he dispelled his own brother. Why do I say Gongsuduan "fleed to" instead of "run to"? Well, that is the quandary for a historian.
Hence, Duke Zhuang confined Wujiang, his mother, in Chenyin and vowed, "Not until I come to the nether world under the ground, I swear that I will never see her again." But soon he was filled with remorse for saying that. When Yingkaosu, a frontier official, heard of what the duke said he had an audience with the duke and brought him some presents. The duke awarded him a feast in return, but Yingkaosu left the meat untouched. The duke asked him why. Yingkaosu replied, "My mother has taken all kind of food I have ever tasted, except the meat bestowed by Your Highness. So please let me save it and bring it home to her." The duke lamented, "You can do your filial duty to your mother, but I do not have the one to serve." Yingkaosu asked, "Allow me, what do you mean by that, Your Highness?" Duke Zhuang told him the truth, also the regrets about it. Yingkaosu observed, "There is nothing to worry about. All Your Highness need to do is to dig out an underground tunnel, letting water emerge, and to meet your mother in the tunnel. In do thing, who can accuse you of breaking your vow?" The duke listened to what Yingkaosu suggested and entered the tunnel to meet his mother, chanting "What a joyful reuinon in the tunnel!" When his mother, Wujiang, got out of the tunnel, she also chanted, "What a joyful reunion outside the tunnel!" Since then, the mother and the son had restored the relationship of mutual affinity they was used to have.
Sagacious man says, "Yingkaosu is the son with purely dutiful love. He not only loves his mother, but also inculcates Duke Zhuang with the love of filial duty. The Book of Songs remarks, "There are always dutiful sons who constantly try to carry out the concept of filial duty to other people." Yingkaosu may be the best model for us to copy.