The state of Qi lost its hegemony, and the Jin state also fell into chaos after Li Ji fell into Jin, while at this time, the state of Chu in the south was growing in strength and prosperity under the rule of King Cheng of Chu. The small states of Zheng, Xu, Chen, Cai, Lu, Wei, Cao, and Song in the Central Plains were mostly attached to Chu, or wavered between Chu and Jin, and Chu was quite hegemonic.

After the accession of Duke Wen of Jin, the situation of Jin was stable, the economy was developed, and the people's livelihood was rested. In this case, there has to be a situation between the Jin State and the Chu State that was predicted by Chong'er in the Chu State at the beginning, "Jin and Chu govern the soldiers, and meet in the Central Plains".

Since Song Xianggong failed to dominate and was defeated by the Chu State, the Song State could only be attached to the Chu State. However, Song Xianggong's son Song Chenggong had a grudge against the Chu people for killing his father, and Song Xianggong had treated the exiled Jin Wengong with great courtesy, so after the Jin State recovered its national strength, Song Chenggong decided to betray the Chu State and turn to the Jin State with old friends. At this time, the two countries of Jin and Chu were fighting each other, and the state of Chu naturally could not tolerate such a blatant betrayal of the Song state, so it united Zheng, Xu, Chen, Cai and other countries to attack the Song state, and surrounded the capital of the Song state.

After receiving the rescue, Duke Wen of Jin convened his ministers to discuss countermeasures, and the doctor of the Jin State said: "To repay the previous favor of the Song State, establish the prestige of the Jin State today, and lay the foundation for the future hegemony, it is in one fell swoop!" Hu Yan further made suggestions: "The state of Chu has just recently formed an alliance with the state of Cao, and has formed a marriage with the state of Wei, we want to rescue the state of Song, and we don't have to confront the powerful Chu army head-on." You can attack the two small states of Cao and Wei first, and Chu will definitely give up besieging Song and go to rescue Cao and Wei. ”

When Chong'er passed through Cao Guo in exile, Cao Gonggong once rudely went to peek at him taking a bath, Chong'er has always been deeply humiliated, and he is angry with Cao Gonggong, and now he agrees to attack Cao Guo. In order to prepare for this war, the Jin State expanded the original second army into three armies, and selected a marshal.

After some twists and turns, they also conquered the defense of the country on the road, and the Jin army finally besieged the capital of Cao State, but the capital of Cao State was strong and deep, and it was difficult to conquer for a while, and the Jin soldiers were killed and wounded countless times. In order to hit the morale of the Jin army, the Cao people hung the corpses of the Jin soldiers on the city wall to show the public, and saw that the comrades who besieged the city were not at peace after their deaths. It was suggested: "This is how they treat our soldiers, and we are stationed next to their ancestral graves to plague their ancestral graves." ”

So Jin Wengong moved the army to the vicinity of the ancestral tomb of the Cao people, and the Cao people saw that everyone was frightened, and the people's hearts were unstable, so they had to collect the corpses of the Jin soldiers who died in the war and send them back to the Jin army in coffins. Duke Wen of Jin ordered the army to attack while the people of Cao were in turmoil, and sure enough, they conquered the capital of Cao State.

Although the Jin army conquered Cao, Chu did not withdraw the army besieging Song as predicted and came back to rescue Cao, but attacked more fiercely. The Song State couldn't resist it, and once again sent people to the Jin State to report the emergency. Duke Wen of Jin said to Marshal Xianzhen: "The Song people have come to the emergency again, if we don't go to the rescue, the Song State will break off relations with us and completely depend on the Chu State; negotiated peace with the State of Chu, but the State of Chu did not agree; But if we want to fight against the Chu State, the Qi State and the Qin State will not support us, how can this be good? ”

Xian Zhen said: "It is better to let the envoys of the Song State send gifts to the Qi State and the Qin State, and ask them to mediate on their behalf." We seize the monarch of Cao State, and then divide the land of Cao State and Wei State to Song State, Chu State and Cao State and Wei State are allies, and they will definitely not agree to reconcile, when the time comes, Qi State and Qin State receive gifts from Song State and are angered by the Chu people's lack of face, can they not start a war with Chu State? Jin Wengong felt justified, so he acted according to the plan.

Seeing that the situation was becoming more and more severe, King Cheng of Chu intended to withdraw his troops, so he sent someone to tell Ling Yin Ziyu, who was leading the army at the front. But Ziyu was arrogant and conceited, because someone once criticized him for not being able to lead troops, and he could only command 300 chariots at most, so he refused to obey the order to withdraw the army, and only sent someone to ask King Chu Cheng for battle, saying: "I don't want to make war achievements, just to block the villain's mouth with facts." Seeing that Ziyu did not obey the order, King Chu Cheng was very angry, and only gave Ziyu a small amount of troops and one hundred and eighty chariots.

Ziyu is not incompetent, before the war, he first sent Wanchun to the Jin military camp to negotiate: "Please restore your army to the position of the monarch of the country, return the land of Cao to Cao, and I will withdraw from the army to relieve the siege of Song." Hu Yan wanted to refuse, but Xianzhen saw the conspiracy, he said: "If the state of Chu said a word that could calm the danger of the three kingdoms of Cao, Wei, and Song, but we refused their request with a sentence and pushed the three kingdoms into the danger of perishing, then we are out of order and unpopular." It is better for us to negotiate with Cao and Wei in private, give them benefits, and then arrest Wanchun to provoke the anger of the Chu State, and then the charge of provoking a war will be the Chu State. "Duke Wen of Jin adopted Xianzhen's suggestion, and Cao and Wei really broke off their friendship with Chu.

Ziyu was very angry when he learned of this and ordered to attack the Jin army, but the Jin army retreated without a fight. The soldiers didn't understand why the monarch didn't dare to fight head-on with the Chu State Ling Yin, so Hu Yan stood up and explained: "Only a famous and justifiable army has combat effectiveness, and without the help of the Chu State, the monarch would not be where he is today." At the beginning of the Chu State, the monarch had agreed with the King of Chu that if the soldiers met, the Jin army would retreat, and now it should be used to repay the Chu State. If we retreat and the Chu army is still aggressive, then it is an unreasonable provocation by the other party. ”

The Jin army retreated all the way, Ziyu led the troops to pursue, all the way to Chengpu (now Linpu City, Fan County, Shandong), Song Chenggong, Qi general Guo Gui Father, Qin general Xiao Zi Yan led a large army to be stationed here, and the Chu army was stationed with its back against the dangerous mountain. Duke Wen of Jin was also hesitant to take into account the favor of King Chu Cheng in the past, and Hu Yan persuaded him: "Let's fight!" If we win, we can dominate the princes, and even if we are defeated, we will not be harmed by the country. ”

At this time, Ziyu sent someone to write a war letter: "Please play with the gentleman, Jun Feng Shi and watch it, and get the minister (Ziyu's name) and Yu Muyan!" Duke Wen of Jin sent a messenger to reply, agreeing to start a war tomorrow: "Dare to bother the doctor, it is said that the second and third sons: ring the car, respect the monarch's affairs, and see you in the court!" ”

The next day, one of the largest wars of the Spring and Autumn period broke out. Duke Wen of Jin ordered 700 of the Jin army to line up in chariots north of Xindi, and sent Xu Chen to lead the army to resist Chen and Cai. Ziyu ordered Ruo Ao's 180 chariots to be the Chinese army, ordered Zixi to lead the left army, Zishang to lead the right army, and threatened to destroy the Jin state.

After the start of the war, the Jin army attacked first, and Xu Chen wrapped his war horse in tiger skins and launched a fierce attack on the armies of Chen and Cai. Chen and Cai's armies were quickly defeated and fled, and Chu's right army was also defeated. In order to lure the enemy into a light advance, Fox Mao set up two large flags to retreat in camouflage, and Luan Zhi also ordered the chariot to drag the branches to escape in camouflage, Ziyu really hit the plan and led the army to pursue. The pioneer of the Chinese army, Yin Qin, led the army to attack horizontally, and the father and son of Fox Mao and Hu Yan led the upper army to attack the left flank of the Chu army at the same time, and the left army of Chu was defeated and soon defeated. Only the main force of the Chinese army led by Ziyu was left to pack up the remnants and fled back to Chu in defeat.

Although the defeat in the Battle of Chengpu did not cause serious losses to the main force of Chu, Chu's plan to go north to the Central Plains to compete for hegemony with the Jin State suffered a serious blow, causing Yin Ziyu to commit suicide. From then on, the state of Chu could only concentrate its efforts on running the south, and the supremacy of Duke Wen of Jin was thus established.

After the Battle of Chengpu, Duke Wen of Jin did not see joy, but sighed worriedly from time to time, and someone asked him: "We have defeated the state of Chu, what is the monarch worried about?" Duke Wen of Jin sighed and said: "I heard that after defeating others, only the saint can be safe and secure, Yin Ziyu, the commander of the Chu State, is still alive, and I don't know when it will make a comeback, how can I be happy?" Who knew that soon after, news came that Ziyu was forced to commit suicide.

It turned out that after the defeat in the Battle of Chengpu, the Chinese army led by Ziyu did not suffer too many losses, so although he was in a low mood, after all, victory and defeat were a common thing in soldiers, and he did not blame himself too much, so he packed up the remnants and went back to Chu. But all the way to the state of Chu, King Cheng of Chu was very angry at his behavior of not obeying orders and blindly greedy for war, which led to the defeat of the Chu army, and sent someone to the army to reprimand Ziyu: "Doctor, if you return to China, then how can I explain to my sons and daughters who died in battle with you in Shen and Xi?" ”

Only then did Ziyu know that the king of Chu had been so disgusted with himself that he had to commit suicide. When the news reached the military camp of the Jin State, Duke Wen of Jin was overjoyed and said: "I defeated the army of the State of Chu outside, and the King of Chu himself killed the powerful ministers inside, and the strength of the State of Chu weakened accordingly inside and outside, I can sit back and relax!" ”

Seeing that the state of Chu was no longer to be worried, Duke Wen of Jin stationed his army in Hengyong (now Yuanyangxi, Henan) in Zheng State, and then regarded himself as the overlord and assembled the princes. The princes and monarchs saw that the Jin army was newly victorious and strong Chu, and no one dared to disobey their wishes, so they came one after another, and even Chen Guo, an ally of Chu who assisted the Chu army in attacking the Jin army during the Battle of Chengpu, also came to the alliance.

When Duke Wen of Jin saw that the princes had arrived, he was very satisfied with his current prestige, but after all, his overlord had not yet been recognized by the Zhou royal family, and he was suspected of being unjustifiable, so he planned to lead the princes to Luoyi to meet King Xiang of Zhou. However, considering that the Jin State had just recovered from the civil strife, and there was a big war with the Chu State, and the strength was seriously consumed, and it was afraid that someone would take the opportunity to rebel if he had to take so many people to Luoyi for a long time, so the Duke of Jin Wen dispelled this idea and sent people to build a palace in Jiantu, preparing to invite King Zhou Xiang here to hold a ceremony to confirm his overlordship.

Before the Battle of Chengpu, the power of the Chu State penetrated almost the entire Central Plains region, and even large countries such as the Qi State were invaded by the Chu people, and small states such as Lu, Wei, Zheng, Chen, and Cai had to submit to the Chu State. At that time, the vassal states of the Central Plains were all brother countries with the surname Ji, while the Chu State was a prince with a different surname, and it had always been regarded as barbarians by the Central Plains countries. For the Zhou royal family and the vassal states of the Central Plains, the defeat of the Chu army by Duke Wen of Jin and the attempt to curb the northward movement of the Chu state were great achievements. What's more, at this time, the Zhou royal family was in decline, and Duke Wen of Jin had made great contributions to King Xiang of Zhou in the rebellion of the prince's belt, so King Xiang of Zhou readily agreed to Duke Wen of Jin's invitation and promised to come in person to reward the Jin army and reward Duke Wen of Jin.

Zheng Guo was originally an ally of Chu State, and used to be a guide for the Chu army during the war, and when Chong'er passed through Zheng State in exile, he was rudely rejected by Zheng Wengong. At this time, Zheng Wengong saw that Chong'er not only became the monarch, but also personally led the army to defeat his backer Chu State, and was deeply afraid that Jin Wengong would hate the events of the year and attack Zheng Guo with the might of the army, so he quickly sent someone to ask for peace with the Jin State. Jin Wengong has been in exile for many years, and he is used to seeing the warmth and warmth of people and the hot and cold world, and he did not make it difficult for Zheng Wengong, and readily agreed to form an alliance with Zheng Guo.

After King Xiang of Zhou arrived at Jiantu, Duke Wen of Jin personally offered prisoners to King Xiang of Zhou, including 100 horses and chariots and 1,000 infantry of the Chu State. Duke Wen of Jin expressed the loyalty of the Jin State to the Zhou royal family by offering prisoners, so King Xiang of Zhou received Duke Wen of Jin with a high standard, and ordered the secretary Yin, Wang Zihu and Shuxing of Neishi to order Duke Wen of Jin to be the uncle of Hou in the name of Zhou Tianzi, so that the hegemony of Duke Wen of Jin was recognized by the Zhou royal family.

After that, on behalf of King Xiang of Zhou, the three envoys gave various ceremonial articles that were in line with the status of the overlord to Duke Wen of Jin, including the two kinds of ceremonial clothes worn in the sacrifice and battle, a red bow, a hundred red arrows, ten black bows, a thousand black arrows, a pot of fragrant wine for worshipping the gods, and 300 tiger guards of the Son of Heaven.

After the reward was completed, the three envoys, on behalf of King Xiang of Zhou, granted the power of controlling the countries and crusading against the unsubordinate to Duke Wen of Jin: "The Son of Heaven tells his uncle: Please respectfully obey the orders of the Son of Heaven, appease the countries of the Quartet, and correct the mistakes of the Son of Heaven. "Duke Wen of Jin thanked him three times in accordance with the etiquette system before he said that he obeyed the order, and then accepted the letter of encouragement, and went in and out to meet King Xiang of Zhou three times in a row, and this set of red tape for Zhou Tianzi to recognize the hegemony of Duke Wen of Jin came to an end.

Soon after, Zhou Tianzi ordered Prince Hu to summon the princes of various countries to meet in the palace of Jiantu, and asked everyone to swear: "Each of them works hard to assist the royal family, do not infringe on each other, and those who violate this oath will be punished by the gods!" Through this alliance, on the one hand, it emphasized that countries should not be conquest at will, and on the other hand, it enabled Jin Wengong to use the identity of "Hou Bo" to crusade against the vassal states that "did not obey the king's orders" for Zhou Tianzi. Not only did the hegemony of the Jin State be recognized by Zhou Tianzi through a series of etiquette, but also prepared a banner of "respecting the king" for the future conquest of the Jin State.