Duke Wen of Jin (Ji Chonger) after he ascended the throne, Duke Wen of Jin reorganized internal affairs, developed production, and managed the state of Jin to become stronger and stronger. He also wanted to be the overlord of the central plains like Duke Huan of Qi. At this time, King Xiang of Zhou sent for help. King Xiang of Zhou had a half brother named taishudai, who joined forces with some ministers to borrow troops from the state of DI and seize the throne. King Xiang of Zhou fled to the state of Zheng with dozens of followers. He issued an order asking the princes of various countries to escort him back to Luoyang. Some of the princes sent people to comfort the son of heaven, and some sent food, but no one was willing to send troops to beat Di people. Someone said to King Xiang of Zhou, “among the princes, only Qin and Jin have the power to defeat the Di people. I’m afraid others are useless.” King Xiang sent messengers to ask Duke Wen of Jin to escort him back to the court. Duke Wen of Jin immediately sent troops to the east to defeat Di Ren, killed Uncle Dai and his gang, and escorted the emperor back to the capital. Two years later, song Chenggong, the son of Duke Xiang of song, came to ask for help. He said that the state of Chu had sent Cheng Dechen, a senior general, to lead the forces of Chu, Chen, Cai, Zheng and Xu to attack the state of song. The ministers all said, “the state of Chu always bullies the princes of the Central Plains. It’s time for the Lord to help countries in difficulties and establish hegemony.” Duke Wen of Jin had long seen that if he wanted to be the overlord of the Central Plains, he had to defeat the state of Chu. He expanded his troops and established three armies to save the state of song. In 632 BC, the Jin army laid down two small states, Cao state and Wei state, which were annexed to Chu state, and captured the monarchs of both countries. King Cheng of Chu did not want to fight against Jin Wen. Hearing that Jin sent troops, he immediately sent someone to order Cheng Dechen to withdraw. But Cheng Dechen thought that the state of song would be taken down sooner or later, and refused to give up halfway. He sent his ministry to King Cheng of Chu and said, “although I dare not say that I will win the war, I will fight to the death.” King Cheng of Chu was very unhappy. He only sent a small number of troops to Cheng Dechen. Chengdechen first sent people to inform the Jin army to release the monarchs of Wei and Cao. Duke Wen of Jin secretly informed the monarchs of the two countries that he promised to restore their monarchy, but asked them to break off diplomatic relations with the state of Chu first. Cao and Wei really did what Duke Wen of Jin said. Chengdechen wanted to save the two countries, but they first broke off diplomatic relations with the state of Chu. At this point, his feet jumped with anger. He shouted, “this is clearly what the old thief Chong’er forced them to do.” He immediately ordered the whole army to rush to the place where the Jin army was stationed. As soon as the Chu army marched, the Jin government ordered it to retreat. Some officers and men in the Jin army couldn’t take it easy. They said, “our commander is the monarch, and the other party’s soldiers are the ministers. How can there be any reason for the monarch to let the ministers?” Huyan explained: “To fight a war, we must first rely on reason. If the king of Chu once helped his Lord, he promised him that if the two countries were at war, the state of Jin would be willing to retreat. Today, we are retreating to fulfill this promise. If we lose faith in the state of Chu, we will be in a bad position. If we withdraw our troops, and if they don’t stop and advance step by step, they will lose reason. It’s not too late for us to fight with them again.” The Jin army retreated 90 Li in one breath and arrived at Chengpu (now the southwest of juancheng, Shandong Province), then stopped and arranged the formation. Some generals of the state of Chu wanted to stop the attack when they saw that the Jin army was retreating. But chengdechen refused. He followed Chengpu step by step, facing the Jin army from afar. Chengdechen also sent people to make a war presentation to Duke Wen of Jin. The wording was very arrogant. Duke Wen of Jin also sent someone to answer, “we have never dared to forget your kindness, so we have to give in here. Now that you are unwilling to understand, you have to compete on the battlefield.” The war began. After the first battle, the general of the state of Jin commanded the army to retreat with two flags. They were still dragging the fallen branches behind the chariot. When the chariot retreated, the ground raised bursts of dust, showing a very flustered appearance. Cheng Dechen was always arrogant and did not pay attention to the Jin people. He chased up regardless of the front and back and hit the ambush of the Jin army. The elite of the Jin army rushed over and cut off Cheng Dechen’s army. The Jin army, which had pretended to be defeated, turned around and attacked back and forth, killing the Chu army in pieces. Duke Wen of Jin quickly ordered that the soldiers should just drive the Chu army away and not pursue it. Cheng Dechen took the defeated and disabled general back on the way. He felt unable to explain to King Cheng of Chu, so he committed suicide. The Jin army occupied the camp of Chu state. After eating the food abandoned by the Chu army for three days, they returned home triumphantly. The news that the state of Jin defeated the state of Chu spread to Luoyi, the capital of Zhou. King Xiang of Zhou and his ministers thought that the state of Jin had made great contributions. King Xiang of Zhou also went to jiantu (now the southwest of Yuanyang, Henan Province, Jianyin Ji’an) to comfort the Jin army. Taking advantage of this opportunity, Duke Wen of Jin built a new palace for the son of heaven in jiantu, and also made an appointment with the princes of all countries to hold a general meeting and conclude an alliance. In this way, Duke Wen of Jin became the overlord of the Central Plains.