It was a crucial victory for the leader Cao Cao (155 AD - 220 AD) in which he led a rebellion against Yuan Shao. He destroyed Yuan Shao's supplies and killed him. This resulted in Cao Cao becoming the military ruler of northern China.
From 196 onwards it became increasingly clear that there would be a confrontation between the two warlords Yuan Shao and Cao Cao for dominion of the north sooner or later. In such an eventuality, the position of Guandu would become of strategic importance. It was close to the Yan Ford on the Yellow River and lay directly on the route to Xuchang. Cao Cao was the first to recognize its importance and in the autumn of 199, he moved forces there and prepared fortifications. The next year, Liu Bei defected from Cao to his rival Yuan Shao. Yuan took the opportunity to mount a campaign in the south and in the first month of 200, his vanguard attacked the garrison of Liyang, just north of the Yellow River. The commander at Liyang, Yu Jin, signalled to headquarters the approach of Yuan Shao. Cao Cao immediately regrouped his troops and stationed 20,000 men at Guandu in preparation for a decisive battle in the new future.
Soon Yuan Shao's main army arrived, boosting his numbers to 110,000, including 10,000 cavalry. His general Yan Liang crossed the Yellow River and attacked the city of Baima. Under the advise of Xun Yu, Cao Cao led a battalion across the Yan Ford on the Yellow River. But this manoevre proved to be only a feint, and as soon as Yuan Shao drew troops from Baima to counter Cao's attack, Cao Cao retreated and struck east to relieve Baima. In the ensuring battle, General Yan Liang was killed and the Yuan troops disastrously routed. After this Cao Cao prepared to abandon the city and evacuated the residents south. Taking advantage of the situation, Wen Chou and Liu Bei, leading 6,000 light cavalry, were sent from the Yuan camp in pursuit. But again, Cao Cao anticipated his opponents' move and had prepared a snare. Horses, equipment and other valuables were discarded and as the enemy troops broke ranks to loot, they were smashed by six hundred elite cavalry. In the chaotic slaughter, the commander Wen Chou was killed. Thus, in the opening moves, Yuan Shao had lost two of his great leaders and his army morale had taken a huge thrashing.
In the aftermath, he reorganised his forces and Liu Bei was sent out to attack Runan, and expose Cao Cao's flank. Ever the strategist, Cao Cao recognised this and wary of fighting under disadvantageous circumstances, commanded a general withdraw to Guandu. At the same time, Cao Ren and Yu Jin were sent to harass the enemy rear. Orders were given for administrators to govern leniently to offset any chance of civilian disruptions in the rear. In the eighth month the Yuan army pushed to Yangwu, directly north of Guandu and began construction on earthen fortifications. The Cao army also began reinforcing their own defences. Both sides harassed each other with ballistas and catapults without effective result. To break the stalemate, it was suggested to Yuan Shao that he use his superior numbers to his advantage and outflank the enemy to attack Xuchang. Yuan, however refused, preferring to wait for the food supply in the Cao army to run out.
Indeed the grain was falling short in Cao Cao's granaries and he considered a withdrawal. Such a situation called for immediate action. Shock troops were dispatched to burn Yuan's grain carts and Yuan Shao was forced to send out for relief food supplies. In the tenth month, Chunyu Qiong's ten thousand-strong force returned with large reserves of grain and lodged around twenty kilometres from the main Yuan camp, in a place called Crow's Nest (Wuchao). The wisdom of such a position was questioned by adjutant Ju Shou, who argued that there were too few troops to guard such an important commodity as grain. A defection soon after from Yuan Shao's ranks alerted Cao Cao to this weakness and he seized the opportunity. Leaving the main camp in the hands of Cao Hong, a force of 5,000 elite infantry was led by Cao Cao himself into enemy controlled territory.
Travelling rapidly under the enemy banner at night and feigning to be Yuan's reinforcements, Cao Cao besieged Chunyu Qiong's garrison and destroyed grain carts.
At such a time of emergency, Yuan Shao refused to send his main forces to relieve Chunyu's defenders, as his commander Zhang He urged him to do. Instead he chose to send a smaller force of light cavalry, whilst attacking Guandu with the bulk of his army. By dawn, Wuchao had fallen to the furious attack and Cao's victorious soldiers then proceeded to defeat the small relief force. At Guandu, Yuan Shao failed to break through and army morale dropped sharply in knowledge of the capture of food supplies. Zhang He surrendered and his battalion burned their weapons. Cao Cao seized the day once more and attacked when the enemy was at its weakest. 70,000 of Yuan's force was destroyed and he lost countless provisions, escaping over the Yellow River with little more than 800 horseman.
The victory was a decisive one; Yuan Shao no longer provided a serious threat to Cao Cao's ambitions and he died a dejected man the next year. Unlike Yuan Shao, Cao knew the value of tactical withdrawals. On the strategic level he could understand and anticipate his opponent's moves and took calculated risks to counter them. The victory of Cao Cao over superior forces lay in his capacity for superior planning and processes on tactical and strategic levels. He rendered his inferior numbers irrelevant with the use of disruption and dislocation. In short, dislocation is the art of cancelling out the enemy's strength. Instead of having to fight a hostile force on its own terms, the friendly force avoids any combat in which the enemy can bring his might to bear. In contrast, Yuan Shao had none of this brilliance and has often been criticised for not heeding the reasonable suggestions of his senior advisers. Certainly this was an important part of his defeat, for if he should have recognised the importance of the grain supply and taken appropriate measures as his counselors advised. The Battle of Guandu will forever be testimony to the fact that superior numbers do not gain victory.Battle of Guandu