While the coalition forces were methodically preparing for war, a sudden invasion disrupted the original battle plan. It turned out that in the area of the southern foot of the present Zhongtiao Mountain, there was a Rong Di called "Mao Rong", Mao Rong and Zheng Guo were far apart, and the Eastern Zhou Dynasty was separated in the middle, and the two forces could not be together.

But at the critical moment of preparing to attack the Song Dynasty, Mao Rong went to Zheng Guo to do something. Judging from the timing of the enemy's invasion, there is reason to believe that Mao Rong was seduced by the Song people.

Mao Rong first crossed the Yellow River in the south, then crossed Luoshui and Yishui, and then invaded all the way east to the territory of Zhengguo. The Zheng army had already marched towards the Song state, but now it had to turn around to meet the Rong army.

At this time, the Rong army was preparing to attack Yiyi, which was the original Yiguo. After the state of Yi was destroyed by Zheng Wugong, it became a large city of Zheng state. Located on the north bank of the Weishui River, Yiyi was the western gate of Zheng State, and once the enemy captured this place, he could enter the hinterland of Zheng State.

Zheng Zhuanggong led the charioteers all the way to the aid of Yiyi, and finally entered Yiyi before Mao Rong launched an attack. The arrival of the monarch boosted the morale of the defenders. Zheng Zhuanggong climbed the city tower, and Gongzi Tu and several doctors followed him. Zheng Zhuanggong looked around and saw that the enemy camp was mainly stationed in the west and north directions - because the terrain in those two directions was flat and open; To the south of Yiyi is Weishui, and the place is narrow, so it is impossible to deploy troops; To the east of the city are rolling hills and dense forests, neither of which is suitable for camping.

Zheng Zhuanggong looked worried, he said: "There are too many enemies, and they are light infantry, and they move quickly; Almost all of our troops are chariot soldiers, and if the enemy intersperses with invasion of our army, the chariots will become a live target for the enemy, and our army will definitely be defeated. ”

"The enemy has not left us with enough troops, but we can use some brave and unscrupulous soldiers as bait to flee towards the hilly terrain as soon as we come into contact with the enemy. The monarch can set up three ambushes between the hills and wait for the pursuers.

"The pursuit of the Rong army is rash and orderly, greedy and not united, defeating and plundering and not giving in to each other, and fleeing for their lives in defeat and not saving each other. The enemy in the front team will be greedy to intercept the spoils of war, and if they are ambushed, they will inevitably turn around and flee. If the front team flees and the rear team does not save it, then the Rong army will have no follow-up reinforcements, and at that time, our army will only need to let go and slaughter. ”

The plan was adopted immediately. In the evening, Zheng's follow-up troops, an infantry that had run to the point of vomiting blood, reached the hilly terrain to the east. The army stopped advancing, resting and waiting for orders.

Zheng Zhuang Gong ordered the army to set up an ambush at the designated place, and it was not allowed to camp or light fires; Make the area look as if there is no one. It was already November, and after the sergeants had eaten the dry rations they had brought with them, they had endured a cold and unbearable night in sweat-soaked clothes and weapons. The Maorong camp held a grand bonfire, and the people ate and drank as if they were not facing an upcoming battle, but a grand wedding.

Early the next morning, the Rong army gathered its army and began to attack the city from both the west and the north at the same time. The enemy's siege equipment was rudimentary, but the offensive was swift; The defense in the city was seriously insufficient, and if there were no reinforcements, the fall of Yiyi would be in the middle of the day.

Zheng Guo's bait soldiers suddenly rushed out of the city gates from the east and south, shouting and slaughtering into the enemy group.

To tell the truth, the initial aggressiveness of the bait soldiers really frightened the Rong army, and the enemy had to stop attacking and line up to meet the enemy. The Zheng people did not want to give the enemy a chance to prepare, and still bluffed to attack the enemy army.

The Rong army did not feel too much pressure, and they realized that the number of Zheng troops was really too small, so they suddenly launched a counterattack. Zheng Ren only symbolically resisted, and immediately threw away his weapon, turned around and fled. The Rong army was in hot pursuit.

The ensuing scene is less like a robbery of refugees than a pursuit of deserters. The baits also seemed to be very cooperative with the enemy's looting, and they took the initiative to throw weapons, armor, jade pendants, and coins all over the entire route of escape. The soldiers were overjoyed, and they casually carried the possessions they had picked up or stolen into their arms or pinned them to their waists, and then continued to run. In fact, by the end of the day, a lot of people have become porters and don't look like soldiers.

The bait soldiers finally led the enemy into the encirclement, and the commander of this ambush was the doctor Zhu Dan. Zhu Dan began to beat the drum, and the ambush soldiers rushed out of the ambush in an instant.

The Zheng archers first fired at the enemy, then violently attacked the heavy-armed, breathless, and overwhelmed raiders with their long weapons, cutting the enemy ranks into four sections.

The enemy, who had been ambushed, threw down his spoils of war and fled, but was strongly resisted by Zheng's army. The Zheng army rushed down from the opposite hilly slope in an orderly manner to attack the enemy, and their repeated attacks inflicted heavy casualties on the Rong army; The enemies outside the encirclement did not dare to turn around and flee, but on the way they were pursued by the Zheng army who had been killed from the city.

The enemy has been crushed, and the chariots of the Zheng army have exerted great power in the process of chasing and fleeing: the chariots can ram and crush the running infantry at will; The archers and the right of the rook willfully killed and wounded the escapees; The rotor mounted on the axle could easily break the legs of infantry and horses.

After the enemy troops outside the ambush circle fled, the Zheng army could safely slaughter the besieged Rong soldiers. Zhu Dan's order was not to accept any surrender, and to kill all of them without leaving anyone behind, so this part of the enemy was completely annihilated. Although this method is cruel, it is extremely deterrent, and Mao Rong will not dare to invade Zheng Guo again for at least a few years.

The Zheng army took advantage of the victory to attack and captured the Maorong camp in one fell swoop.

The Zheng people won a great victory, but they were delayed too much time in the battle against Maorong, and the harsh winter had arrived, and the temperature had dropped to the extreme, and the coalition forces could not carry out a war against the Song State, so they returned to China and waited for the next year to fight again.