初，鄭武公娶于申，曰武姜，生莊公及共叔段。莊公寤生，驚姜氏，故名曰寤生，遂惡之。愛共叔段，欲立之。亟請于武公，公弗許。

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.

及莊公即位，為之請制。公曰：“制，巖邑也，虢叔死焉。佗邑唯命。”請京，使居之，謂之京城大叔。祭仲曰：“都城過百雉，國之害也。先王之制：大都不過參國之一，中五之一，小九之一。今京不度，非制也，君將不堪。”公曰：“姜氏欲之，焉辟害？”對曰：“姜氏何厭之有！不如早為之所，無使滋蔓，蔓難圖也。蔓草猶不可除，況君之寵弟乎！”公曰：“多行不義，必自斃，子姑待之。”

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 square zhi, that will imperil our state. According to the established rule, a metropolitan area can only be as large as one third of the capital in terms of area; a middle-sized city, one fifth; and a small-sized town, one ninth. 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 the issue in time and not let the root of trouble grow; otherwise, it will be very hard to tackle. 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."

既而大叔命西鄙北鄙貳于己。公子呂曰：“國不堪貳，君將若之何？欲與大叔，臣請事之；若弗與，則請除之。無生民心。”公曰：“無庸，將自及。”大叔又收貳以為己邑，至于廩延。子封曰：“可矣，厚將得眾。”公曰：“不義，不暱，厚將崩。”

Later on, Marquis Gongsuduan annexed a fief of Zheng on the west frontier and a rebel fief in the north. A pedigreed gentleman, Lu, advised, "There should not be two dukes coexisting within a state. What is 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, "There is no need of getting rid of him. He will suffer from his own actions." Before long, Marquis Gongsuduan further occupied two other fiefs as his own and expanded his territory to Linyan. Lu once again 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 his final collapse."

大叔完聚，繕甲兵，具卒乘，將襲鄭。夫人將啟之。公聞其期，曰：“可矣！”命子封帥車二百乘以伐京。京叛大叔段，段入于鄢，公伐諸鄢。五月辛丑，大叔出奔共。

Now Marquis Gongsuduan, reconstructing the walls, gathering more people, repairing weapons and armor, and preparing carriages and soldiers, was going to launch a surprise attack on Zheng. Wujiang, his mother, would stand 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 part of the punitive expedition to Jing. The people of Jing then rebelled against Marquis Gonsuduan, so he fled to Yan, and Duke Zheng continued to pursue him. At last, on the 23rd day of May, Marquis Gongsuduan further fled to Gong. 

書曰：“鄭伯克段于鄢。”段不弟，故不言弟；如二君，故曰克；稱鄭伯，譏失教也；謂之鄭志。不言出奔，難之也。

The 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, 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.

遂寘姜氏于城潁，而誓之曰：“不及黃泉，無相見也。”既而悔之。潁考叔為潁谷封人，聞之，有獻于公，公賜之食，食舍肉。公問之，對曰：“小人有母，皆嘗小人之食矣，未嘗君之羹，請以遺之。”公曰：“爾有母遺，繄我獨無！”潁考叔曰：“敢問何謂也？”公語之故，且告之悔。對曰：“君何患焉？若闕地及泉，隧而相見，其誰曰不然？”公從之。公入而賦：“大隧之中，其樂也融融！”姜出而賦：“大隧之外，其樂也洩洩。”遂為母子如初。

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 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 the 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 one to serve." Yingkaosu asked, "Allow me, what do you mean by that, Your Highness?" Duke Zhuang told him the truth, as well as his regrets about it. Yingkaosu observed, "There is nothing to worry about. All Your Highness needs to do is dig out an underground tunnel, let water emerge, and meet your mother in the tunnel. In so doing, 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 reunion 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 have restored the relationship of mutual affinity they used to have. 

君子曰：“潁考叔，純孝也，愛其母，施及莊公。《詩》曰：‘孝子不匱，永錫爾類。’其是之謂乎！”

A sage man says, "Yingkaosu is the son of purely dutiful love. He not only loves his mother but also instills in Duke Zhuang 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.