Battle of Mobei The Battle of Mobei ( ) was a military campaign fought in the northern part of the Gobi Desert . It was part of a major strategic offensive launched by the Han Dynasty in January , 119 BC , into the heartland of the nomadic Xiongnu . The battle was a success for the Han , whose forces were led by Wei Qing and Huo Qubing . Background . Military tension had for a long time existed between ancient China and the northern " barbarians " , mainly because the fertile lands of the prosperous agricultural civilization presented attractive targets for the militaristic nomadic tribes . Throughout ancient Chinese history , protecting the northern borders from nomadic raids had been a military priority . During the Zhou Dynasty , northern vassal state s such as Yan , Zhao and Qin resorted to defensive strategies , constructing elongated fortresses that served as the precursors of the Great Wall of China . During the Qin Dynasty , the first emperor Qin Shi Huang conscripted thousands of civilian labourers to perfect the Great Wall in order to reinforce military campaigns along the northern border . Han Dynasty China and the nomadic Xiongnu Empire had a very bitter relationship . The Xiongnu were initially a group of steppe tribes kept in check by the Qin Empire ' s military offensives under General Meng Tian . With the collapse of the Qin Dynasty and the subsequent Chinese civil war , the Xiongnu gained the opportunity to become unified under Modu Shanyu and quickly expanded into a powerful tribal confederacy that ruled over a vast territory across Central and East Asia . The Xiongnu then invaded and occupied the fertile Hetao Grassland . When the Chu - Han contention concluded , Emperor Gao recognized the threat posed by its hostile northern neighbour and in 200 BC launched a massive campaign . After the Han army was lured into an ambush and encircled by 300 , 000 elite Xiongnu cavalry for seven days , the siege was relieved only after messengers were sent to bribe the Shanyu ' s wife . Following this failure , the Han emperor realized that the nation , which just recovered from a massive civil war , was not yet strong enough to confront the Xiongnu ; therefore , he resorted to the so - called " marriage alliance " , or " heqin " , in order to ease hostility and buy time to strengthen the nation . Despite the humiliating periodic " heqin " and giving of gifts , the Han borders were still frequently raided by Xiongnu forces over the next seven decades . During his reign , Emperor Wu of Han decided that the nation was finally strong enough to solve the Xiongnu problem . The " peaceful " atmosphere was broken in 133 BC after a large ambush operation was staged at Mayi but aborted after the Xiongnu discovered the trap and retreated . In 129 BC , the Han forces had their first proper victory against the Xiongnu under the command of the young Wei Qing with a long - distance raid on the Xiongnu holy site at Longcheng ( 蘢城 ) . Over the next ten years , Emperor Wu repeatedly deployed Wei and his vigorous nephew Huo Qubing against Xiongnu forces thus recapturing large areas of land and dealing devastating blows . Evicted by the defeats , Yizhixie Chanyu ( 伊稚邪 ) took Zhao Xin ' s advice , and the Xiongnu tribes retreated to the north of the Gobi Desert , hoping that the barren land would serve as a natural barrier against Han offensives . In 119 BC , Emperor Wu planned a massive expeditionary campaign . Chinese forces were deployed in two columns , each consisting of 50 , 000 cavalry and over 100 , 000 infantry . Wei Qing and Huo Qubing served as the supreme commanders , and set off from Dai Prefecture ( 代郡 ) and Dingxiang ( 定襄 ) . The battles . The initial plan called for Huo Qubing to attack from Dingxiang but information from a Xiongnu prisoner of war suggested that the Chanyu ' s main force was deployed to the east at Dai Prefecture , although the information actually proved to be false . Emperor Wu , who had been distancing Wei Qing and giving the younger Huo more attention and favour , ordered the two columns to switch routes in the hope of letting Huo ( who was preferentially assigned the most elite troopers ) engage the Chanyu . The Eastern ( Dai Prefecture ) Theatre . The eastern theatre was quite straightforward , as the Han forces deployed were superior to the opposing Xiongnu forces . Huo Qubing ' s forces set off from Dai Prefecture , marched over 1 , 000 miles and directly engaged the forces of the Xiongnu ' s Worthy Prince of the East ( 左賢王 , " Wise King of the East " ) . The battle was swift and decisive , as the Worthy Prince ' s forces were no match for Huo ' s elite cavalry . The Huo ' s army quickly encircled and overran their enemy , killing 70 , 443 men and capturing three Xiongnu lords and 83 nobles . Huo Qubing ' s forces suffered a 20 % casualty rate but were quickly resupplied locally from their capture . He then went on to conduct a series of rituals upon arrival at the Khentii Mountains ( 狼居胥山 , and the more northern 姑衍山 ) in order to symbolize the historic Han victory , then continued his pursuit as far as Lake Baikal ( 瀚海 ) , effectively annihilating the Xiongnu clan . A separate division led by Lu Bode ( 路博德 ) , set off on a strategically flanking route from Right Beiping ( 右北平 ) , joined forces with Huo after arriving in time with 2 , 800 enemy kills . The combined forces then returned in triumph . The Western ( Dingxiang ) Theatre . The western theatre , although not regarded with as much expectation from Emperor Wu , proved more dramatic . Wei Qing ' s force , setting off from Dingxiang , was comparatively weaker than its eastern counterpart , as it consisted mainly of leftovers from Huo Qubing ' s preferential picks . Wei Qing also had other liabilities — he had five generals under his command that required assignments , including an old but enthusiastic Li Guang . Li Guang insisted that he wanted a vanguard position as promised by Emperor Wu , who also secretly messaged Wei " not to " do so as Li was well known to be jinx ed with " bad fortune " . Wei Qing then assigned Li Guang to combine forces with Zhao Shiqi ( 赵食其 / 趙食其 ) on a barren eastern flanking route , an arrangement that Li protested against and angrily stormed out of the main camp . The Han army mobilized as planned . After a journey of over 500 miles , they encountered the Chanyu ' s main forces of 80 , 000 cavalry . This was unexpected , as the original strategy was to let Huo Qubing ' s elite troops deal with Chanyu ' s elite cavalry ( the reason that the two Han columns switched route ) . The Xiongnu forces , however , had been long waiting in anticipation to ambush their adversary . The Han forces , on the other hand , were tired and outnumbered , especially since the eastern division had not yet arrived on the battlefield . Without hesitation , the Xiongnu charged the Han forces with a 10 , 000 - strong vanguard of cavalry . Wei Qing recognized the odds against him and quickly took defensive countermeasures . He ordered his troops to arrange heavy - armoured chariot s ( 武刚车 / 武剛車 ) in a ring formation s , creating mobile fortresses that provided archer s , crossbowmen and infantry protection from the Xiongnu ' s powerful cavalry charges , and allowed Han troops to utilize their ranged weapon s ' advantages of precision . A 5 , 000 - strong force of cavalry was deployed to reinforce the array and eradicate any Xiongnu forces that managed to infiltrate the ringed chariots . This tactic proved effective in countering the momentum of the nomadic cavalry , as the Xiongnu forces were unable to breach the Han army ' s lines . With the Xiongnu ' s initial energy neutralized , the battle solidified into a stalemate with neither side making significant gains or losses . This stalemate lasted until dusk , when a sandstorm obscured the battlefield . Knowing that this was his chance , Wei Qing sent in his main force . The Han cavalry used the low visibility as cover and encircled the Chanyu ' s army from both flanks . The Xiongnu ' s lines were overwhelmed , and their morale broken by the sight of Han soldiers attacking them in the darkness . Seeing that his forces were completely overrun , the Chanyu escaped under the escort of only a few hundred men . The Han forces killed over 19 , 000 enemies and pursued the remainder another 100 miles to the Khangai Mountains where they besieged then captured the Fortress of Zhao Xin located in the Orkhon Valley . After a day spent regrouping and receiving fresh supplies , the Han forces burned the stronghold to the ground , before returning in triumph . The eastern division , commanded by Li Guang and Zhao Shiqi , got lost in the desert and missed the battle entirely , only rejoining the main force on Wei Qing ' s way home . As a result , Li and Zhao were summoned to a court martial for failing to accomplish orders and putting the battle strategy at risk . Li Guang , frustrated and humiliated as this was his last chance to obtain sufficient battle distinctions to receive a marquessate as a reward , committed suicide to preserve his honour . In the western theatre the battle proved more strategically decisive . Chanyu ' s main forces was so badly defeated that they were unable to recover . The Chanyu went missing for over 10 days , resulting in his tribe presuming he was dead and installing a new leader who had to be removed after the Chanyu finally reappeared . The Xiongnu were forced to retreat further north with their threat to the Han Dynasty ' s northern border largely obliterated . Aftermath . The costs of the victorious campaigns over the Xiongnu in the ten years from 129 to 119 BC were enormous : the Han army lost almost 80 % of their horses on these expeditions , due to combat as well as non - combative losses such as the harsh journey and plague caused by the Xiongnu contaminating the water supply with dead cattle . Economic pressure on the central Han government led to new tax es being introduced , increasing the burden on average peasants . The population of the Han Empire dropped significantly as a result of famine and excessive taxing to fund military mobilisations . The Xiongnu , however , suffered a more lethal blow , as their military losses would reflect directly on their economy . Apart from loss of manpower due to wartime casualties and diseases , the nomadic Xiongnu lost millions of livestock , their vital food resource , to the Han army , and the war left large proportion of the remaining cattle suffering miscarriages during their reproductive seasons . Furthermore , the loss of control over the fertile southern grassland meant that Xiongnu had to hole up in the cold , barren land of the northern Gobi Desert and Siberia , struggling to survive . As a result , there was a true ceasefire between the Han Dynasty and Xiongnu for seven years , which ended after a Xiongnu raid in 112 BC at Wuyuan . The Xiongnu , however , never recovered to the strength of their past glory days , and would break apart into smaller clans in the coming decades .