The morale of the army was disorganized and defeated at Shenhepi
During the Sixteen Kingdoms period, countries attacked each other, all wanting to eliminate hostile forces and achieve the great cause of unification, so wars continued. Tuoba Gui established the Northern Wei Dynasty. After establishing his foothold, he attempted to go south and compete in the Central Plains. Therefore, the Houyan in the Central Plains region became a stumbling block on its way south. At that time, from the perspective of the military strength of both sides, Later Yan had a slight advantage, but due to internal struggles for power and political instability, the country was not as united as the Northern Wei. In April of the 20th year of Taiyuan in the Eastern Jin Dynasty (395), Tuoba Gui led his army to approach the northern border of Later Yan. Murong Chui, the leader of the Later Yan Kingdom, sent Prince Murong Bao and others to lead an army of nearly 100,000 people out of Wuyuan (now north of Shouyang, Shanxi) to attack. Wei, the two sides began a war. The chief historian of the Northern Wei Dynasty proposed a plan to Tuoba Gui and said: The Yan army is underestimating us, so we should show our weakness to make them fall. Tuoba Gui thought so, so he led his army to avoid the enemy's attack and crossed the Yellow River westward. Murong Bao marched to Linhe (now Linhe, Inner Mongolia) without fighting. He felt quite proud and prepared to cross the river to pursue the Wei army and penetrate deep into the hinterland of the Northern Wei Dynasty. At this time, Tuoba Gui fortified the river, ambushed the Later Yan envoys, and spread the news that Murong Chui was dead. The soldiers of the Later Yan army believed it, and the morale of the army was unstable. During the stalemate, Tuoba Gui sent troops to cut off the retreat of the Later Yan army. . After hearing the news that "Murong was dying", an incident broke out among the generals of the Later Yan army. Murong Lin, the king of Zhao, claimed to be the lord of the Later Yan Kingdom, but was killed after the incident was revealed. The morale of the army became even more unstable. Murong Bao saw the fighting spirit of the army and failed to cross the river. In addition, he missed his father. situation, so he decided to withdraw his troops. He burned all the boats that were intended to cross the river, thinking that the Yellow River was not frozen and it would be difficult for the Wei army to cross the river to pursue him, so he did not take precautions when withdrawing his troops. The rear army did not set up a guard post. Unexpectedly, a few days later, a cold wind came suddenly and the Yellow River froze. Tuoba Gui led 20,000 elite cavalry across the Yellow River and attacked the Yan army. When the Yan army retreated to Shenhebei (now southeast of Datong, Shanxi), it was violently attacked by the Wei army. Tens of thousands of troops were lost. The commander Murong Bao escaped alone. The Yan army was greatly damaged after this battle.
After this battle, the Yan army blindly penetrated deep into the Northern Wei Dynasty, lost contact with the rear, and was already at a disadvantage. When confronting the enemy on both sides of the Yellow River, they were bewitched by rumors and internal changes occurred. The morale of the army was in chaos, and signs of defeat appeared. If there is no defense when withdrawing, and there is interception in front and pursuit in the rear, failure is inevitable. In war, only when the morale of the military is stable can morale be strong, as can be seen in this battle.