In 636 BC, Zhou Tianzi, who had been offline for a long time, had a movement, and the queen of Zhou Xiang, Kui Shi, had an affair with her uncle and was deposed by King Xiang. Kui is the daughter of the Di people. The Di people resented king Xiang for this. Uncle Zhou and Tao Zi took the opportunity to lead Uncle Feng to unite with the Di army to attack the King of Xiang. King Xiang fled to present-day Gongyi, Henan. After the Defeat of the Zhou Army, King Xiang took refuge in the State of Zheng (present-day Xiangcheng, Henan) and sent envoys to the various princely states. Qin Mugong had no reason to march into the Central Plains, and took this opportunity to lead his troops to the east to help Zhou Tianzi. The Jin state group of ministers discussed: "The best way to fight for hegemony is to support Zhou Tianzi, the Zhou royal family and the Jin state are the same as the Surname of Ji, if the Jin state does not preemptively escort Zhou Tianzi back to Beijing and falls behind the Qin state, it will not be able to give orders in the world, and respecting the King of Zhou today is the capital of the Jin state to dominate." "The king of Zun yi used to gain political superiority and establish a hegemonic foundation.
Duke Wen of Jin dismissed the Qin army and personally led the Jin army south to attack ShuDai and capture it. In early April, King Xiang was restored to the throne, and zhou Tianzi gave Yangfan, Wen, And mao (southwest of present-day Hui County, Henan) and yuan (present-day northwest of Jiyuan, Henan) to Duke Wen of Jin. The southern territory of Jin was expanded to the south of the present-day Taihang Mountains and north of the Yellow River, providing favorable conditions for its future attempt to dominate the Central Plains.
After the stable situation was established, it began to sort out internal affairs, build roads, reduce taxes, and attract investment from the political and economic points of view, reuse the meritocrats in terms of talent, and rectify military education. A large number of old clans who were persecuted during the jin huigong and jin huaigong era were used, and people with the surname of Ji were appointed as internal affairs officials, and talented people with different surnames served as officials in remote areas. The princes enjoyed the tribute, the doctor collected the taxes of Caiyi, distributed to the shi clan's land, the general commoners supported themselves, the industrial and commercial officials received the fenglu, the servants received rations according to their duties, the food of the courtiers was taken from the doctor's Jiatian, and the fox was made the xiang and the first was the marshal; Let Zhao Wan, Xu Chen, Luan Zhi, Ji Que and others assist him in governing the country; let Hao Qin and Huo Bo lead the army; let Jia Tuo and YangZi make ceremonies; let Wei Yi and Xun Bo resist the Rong people in the north. Formulate rules and regulations for officials, act according to the law, establish reputations, and cultivate virtues. Reward those who have fled with them and all those who have meritorious service, and give them great merit to the city, and award knighthood to the small merit. The Second Army of the Jin Dynasty was expanded into three armies, with Hao Gu commanding the Chinese army, Fox Yan commanding the upper army, and Luan Zhi commanding the lower army. Tax relief, favors, abandonment of prohibitions, distribution of wealth to the widowed, relief of the poor, and support of the wealthless. Tariffs were reduced, roads were built, trade was facilitated, and peasants were relieved of their labor. Encourage the development of agriculture, promote mutual help, and save money to make resources sufficient. In terms of production, it calls for improving tools, benefiting the people, and rewarding reclamation; in terms of trade, taxes have been lowered, and neighboring merchants have been actively recruited.
In 632 BC, the State of Chu, which had always wanted to step into the Central Plains, sent troops to attack the State of Song, and the State of Song sent people to the State of Jin for help. Jin Wengong then summoned the generals to discuss how to save Song. At that time, the situation was: I wanted to intercede with the State of Chu, afraid that the State of Chu would not be willing, such as going to war with Chu, I was not very willing, and I was afraid that Qi and Qin would not approve, and later came up with a method: first agree to the State of Song, and explain the reasons, ask him to contact Qi and Qin first, ask Qi, Qin and Chu to negotiate, and send some gifts to Qi and Qin. The Jin Dynasty first sent troops to cut down Cao and Wei, destroyed Cao and Wei, and divided some of their land to the Song to compensate for the losses of the Song people. When King Cheng of Chu saw that Jin wanted to save Song, he told his general Ziyu not to approach the Jin division to engage him, saying: "The Marquis of Jin fled outside for nineteen years before returning to the Jin kingdom, he has experienced all kinds of dangers, and he understands that this is determined by Providence, and such a person cannot fight with him." "Tell Ziyu to retreat in spite of difficulties." However, Ziyu refused to listen and still wanted to fight with the Jin people, so he sent someone to ask King Cheng for a battle, saying, "I don't dare to say that I must make meritorious deeds, but I just want to block the mouths of those who gossip." ”
Ziyu led an army to attack the Jin army. As soon as the Chu army launched an attack, the Jin army retreated. The officers of the Jin army were puzzled: "Why should we retreat, this is too humiliating, and the Chu army is already exhausted, why should we flee?" Jin Wengong replied, "Once upon a time, when I fled to the Chu Kingdom, I agreed with King Cheng of Chu that if Jin and Chu were to fight, the Jin army would retreat backwards to the land of Sanshe, so how could I renege on my promise?" "Three houses, that is, ninety miles." The Chu army pursued forward, and the Jin army retreated backwards, retreating ninety miles. Until retreating to Chengpu City, the Chu army that was chasing after the Jin army also stopped at Chengpu and waited with the Jin army. In order to lure the Chu army, Luan Zhi, the commander of the Jin Army, dragged the branches of the trees with a vehicle, stirring up dust and making the Chu army think that it was defeated and fled. This move was indeed effective, and ZiYu thought that the Jin army was defeated and retreated, so he ordered the left army of the Chu army to pursue. When the left army pursued, there was an emptiness on the left side of the Chu army, the Jin army and the Shang army jointly attacked the Chu left army, the Chu left army was defeated, Zi Yu saw that the left and right armies of the Chu state were defeated, ordered the Chinese army to stop the pursuit, and led the army away from the battlefield. Because Ziyu commanded the Chinese army properly, the Chu army did not suffer much loss.
This war of Jin and Chu ended with the victory of the Jin state, because the location was in Chengpu, so later generations called this war the Battle of Chengpu.
The Battle of Chengpu was a major battle between the Jin and Chu states after the alliance of Qi and Chu zhaoling and the battles of Song and Chuhong, which was of great significance in the history of the Spring and Autumn Period. It suppressed the momentum of the Chu state's northward advance, stabilized the situation in the Central Plains, and achieved the hegemonic status of the Jin State in the Central Plains
There were two things that Duke Wen of Jin did not do that Duke Huan of Qi did not do. That is to quell the internal turmoil in the kingdom and defeat the Chu state by force. These two feats are enough to enter the ranks of the five masters. After the death of Duke Wen of Jin, the hegemony of the Jin State did not fall, which was also incomparable to the Duke of Qi Huan. Therefore, in terms of merit alone, Qi Huangong is still inferior to Jin Wengong. However, Jin Wengong was inferior to Qi Huan in terms of virtue, such as inviting tunnels, guarding Hou, carrying the Tianzi to Hunt Heyang, and so on, disrespecting the Tianzi. Therefore, in the Five Lords, he should be ranked behind Qi Huangong.