Wei Qing - The Battle of Mobei and Involvement in Li Guang's Death

The Battle of Mobei and Involvement in Li Guang's Death

In 119 BC, Wei, as the Grand Commander of the armed forces, would be involved in a battle controversially leading to the death of another famous general, Li Guang. In this engagement, Emperor Wu broke the normal pattern of reaction against Xiongnu attacks by making a major excursion against Xiongnu's headquarters in the north of the Gobi Desert. This is known to history as the Mobei Campaign ("campaign of the desert's north"). Wei and Huo were in command of the two main armies. Under Wei's command were four other generals Li, Gongsun He, Zhao Yiji (趙食其) and Cao Xiang (曹襄). Contrary to the arrangements promised to Li by Emperor Wu, where he would command the advance division, Emperor Wu secretly told Wei not to assign Li to important missions due to Li's history of "bad lucks". Wei, after the army had already departed, merged Li's forces with Zhao's and ordered them to take an eastern side route through a barren region. According to the historian Sima Qian, Wei had done this to give his old friend Gongsun Ao, who had recently been stripped of his title, a chance to win a major battle and be re-promoted. However, it should be noted that sending Generals of Front (前將軍, namely Li) and Right (右將軍, namely Zhao) on flanking routes was Wei's typical tactical arrangement. This was evidenced by his deployment of Zhao Xin and Su Jian, who were Generals of Front and Right respectively during the less-than-successful 123 BC campaign.

Wei's army unexpectedly encountered Chanyu Yizhixie's main forces, who was waiting in anticipation of ambushing the Han army. Despite being significantly outnumbered and fatigued after the long journey, Wei was able to counter Xiongnu's cavalry charge with archery defence created by heavy-armored chariots arranged in ring formations, which was reinforced with cavalry counteroffensives. (This defence would be evaluated as one of the most effective against cavalry by many Chinese tacticians later, including Yue Fei.) Late into the battle, seizing the moment of a sandstorm (with poor visibility), Wei broke the stalemate and launched bilateral flanking attacks with his cavalries. This decisive move shattered the Chanyu's line, nearly capturing him and completely overrunning his forces, killing over 10,000 Xiongnu soldiers in the process. The Han army pursued all the way to the modern Ulan Bator region, destroying the Xiongnu stronghold Zhao Xin Castle (趙信城) before returning in triumph with a total of about 19,000 enemy kills. Chanyu Yizhixie was forced to escape with very few men, lost communication with his tribe for days, and did not return until his clan presumed his death and installed a new Chanyu. This was a narrow but critically significant victory for the Han empire. Xiongnu was greatly weakened to the point that they would huddle up into the barren northern Gobi desert (leading to decline of their population), and unable to raid south for the next few decades. The next major Xiongnu invasion did not occur until after the Han dynasty collapsed, some 400 years later during the Jin Dynasty.

Meanwhile, Li and Zhao got lost in the desert and failed to arrive in time for battle, despite meeting little Xiongnu resistance. As the battle ended, Li and Zhao were both summoned for court martial on the charge of failure to accomplish orders. Feeling humiliated over the charges against him and frustrated over missing his final chance at martial glory, Li committed suicide rather than to face the court. Many people blamed Wei for causing Li's death, including historian Sima Qian as well as Li's youngest son Li Gan (李敢), who was a subordinate of Huo Qubing at the time. Li Gan later went to Wei's home and assaulted him. Wei decided to let the matter slide, but Huo was greatly angered that his subordinate had the temerity to attack his uncle. Huo thus shot and killed Li Gan during a hunting trip.