Cao Hong； who displayed very great valor； burst into the press of battle and met Yuan Tan face to face。 The two slashed and hammered at each other； and Yuan Tan was killed。
Guo Tu saw that his side was wholly disorganized and tried to withdraw into the shelter of Nanpi。 Yue Jing saw this and opened a tremendous discharge of arrows so that Guo Tu fell and the moat was soon filled with dead。
The city of Nanpi fell to Cao Cao。 He entered and set about restoring peace and order。 Then suddenly appeared a new army under two of Yuan Xi's generals； Jiao Chu and Zhang Neng。 Cao Cao led out his troops to meet them； but the two manders laid down their arms and yielded。 They were rewarded with the rank of lordship。
Then Zhang Yan； the leader of the Black Hills Brigands； came with one hundred thousand troops and gave in his submission。 He was made General Who Pacifies the North。
By an order of Cao Cao； the head of Yuan Tan was exposed； and death was threatened to anyone who should lament for him。 Nevertheless a man dressed in mourning attire was arrested for weeping below the exposed head at the north gate。 Taken into Cao Cao's presence； he said he was Wang Xiu and had been an officer in Qingzhou。 He had been expelled because he had remonstrated with Yuan Tan。 But when the news of Yuan Tan's death came； he had e to weep for his late master。
〃Did you know of my mand？〃 said Cao Cao。
〃I knew it。〃
〃Yet you were not afraid？〃
〃When one has received favors from a man in life； it would be wrong not to mourn at his death。 How can one stand in the world if one forgets duty through fear？ If I could bury his body； I would not mind death。〃
Cao Cao said； 〃And there were many such as this in the north。 What a pity that the Yuan family could not make the best of them！ But if they had done so； I should never have dared to turn my eyes toward this place。〃
The intrepid mourner was not put to death。 The remains of Yuan Tan were properly interred； and Wang Xiu was well treated and even given an appointment。
In his new position Wang Xiu was asked for advice about the best way to proceed against Yuan Shang； who had fled to his second brother； but Wang Xiu remained silent； thereby winning from Cao Cao renewed admiration for his constancy。
〃He is indeed loyal！〃 said Cao Cao。
Then he questioned Guo Jia； who advised him； saying； 〃Give Yuan Xi's former generals the mand and ask them to attack Youzhou。〃
Whereupon Jiao Chu and Zhang Neng were given the mand and reinforced by the armies under Lu Xiang； Lu Kuang； Ma Yan； and Zhang Zi to bring about the surrender of Yuan Xi and Yuan Shang。 Then six generals； to attack Youzhou along three routes。 Other armies led by Li Dian； Yue Jing； and Zhang Yan were sent against Gao Gan at Bingzhou。
The two Yuan Xi and Yuan Shang heard of Cao Cao's advance with dismay for they had no hope of successful resistance。 Therefore they abandoned Youzhou and hastily marched into Liaoxi to seek refuge with the Wuhuan tribespeople in the frontier Wuhuan State。
Then Wuhuan Chu； new Imperial Protector of Youzhou； was not disposed to incur the enmity of the powerful Cao Cao； so he called his subordinates together to swear them to support him。
Wuhuan Chu said； 〃I understand that Cao Cao is the most powerful man of the day； and I am going to support him； and those who do not go with me I shall put to death。〃
Each in turn smeared his lips with the blood of sacrifice and took the oath； till it came to the turn of Han Heng。
Instead he dashed his sword to the ground； crying； 〃I have received great promotions and benefits from the Yuans。 Now my lord has been vanquished。 My knowledge was powerless to save him； and my bravery insufficient to cause me to die for him： I have failed in my duty。 But I refuse to mit the crowning act of treachery and ally myself with Cao Cao。〃
This speech made the others turn pale。
The chief said； 〃For a great undertaking； there must be lofty principles。 However； success does not necessarily depend upon universal support； and since Han Heng is actuated by such sentiments； then let him follow his conscience。〃
So Wuhuan Chu turned Han Heng out of the assembly。 Wuhuan Chu then went out of the city to meet and wele Cao Cao's army and rendered his submission。 He was well received and the title given him of General Who Guards the North。
Then the scouts came to report： 〃Generals Li Dian； Yue Jing； and Zhang Yan had marched to Bingzhou； but that Gao Gan had occupied Huguan Pass and could not be dislodged。〃
So Cao Cao marched thither himself。 The defender still maintaining his position； Cao Cao asked for plans。 Xun You proposed that a band should go over pretending to be deserters。 Cao Cao assented and then called the two Lu Xiang and Lu Kuang； to whom he gave whispered orders。 They left with their panies。
Soon they came near the pass and called out； saying； 〃We are old officers in Yuan Shao's armies forced into surrender to Cao Cao。 We find him so false and he treats us so meanly that we want to return to help our old master。 Wherefore quickly open your gates to us。〃
Gao Gan was suspicious； but he let the two officers e up to the pass； and when they had stripped off their armor and left their horses； they were permitted to enter。
And they said to Gao Gan； 〃Cao Cao's troops are new to the country and not settled。 You ought to fall upon their camp this very evening。 If you approve； we will lead the attack。〃
Gao Gan decided to trust them and prepared to attack； giving the two brothers the leadership of ten thousand soldiers。 But as they drew near Cao Cao's camp； a great noise arose behind them and they found themselves in an ambush attacked on all sides。 Realizing too late that he had been the victim of a ruse； Gao Gan retreated to the pass； but found it occupied by Li Dian and Yue Jing。 Gao Gan then made the best of his way to the Chieftain of the Xiongnu People。 Cao Cao gave orders to hold the passes and sent panies in pursuit。
When Gao Gan reached the boundary of the Xiongnu State； he met Ce Xian； the Khan of the northern tribespeople。
Gao Gan dismounted and made a low obeisance； saying； 〃Cao Cao is conquering and absorbing all the borders and your turn； O King； will e quickly。 I pray you help me and let us smite together for the safety of the northern regions。〃
Ce Xian the Khan replied； 〃I have no quarrel with Cao Cao。 Why then should he invade my land？ Do you desire to embroil me with him？〃
He would have nothing to do with Gao Gan and sent him sway。 At his wits' end； Gao Gan decided to try to join Liu Biao and go southward so far on his journey as Shanglu when he was taken prisoner and put to death by Governor Wang Yan。 His head was sent to Cao Cao； and Wang Yan received lordship for this service。
Thus Bingzhou was conquered。 Then Cao Cao began to discuss the overthrow of the Wuhuan State。
Cao Hong； speaking in the name of other officials； said； 〃The two Yuan Xi and Yuan Shang are nearly done for and too weak to be feared。 They have fled far into the Sea of Sand。 If we pursue them thither； it may bring down Liu Biao and Liu Bei upon the capital。 Should we be unable to rescue it； the misfortune would be immense。 Wherefore we beg you to return to Xuchang。〃
But Guo Jia was of different advice。
〃You are wrong；〃 said he。 〃Though the prestige of our lord fills the empire； yet the peoples of the desert； relying upon their inaccessibility； will not be prepared against us。 Wherefore I say attack； and we shall conquer them。 Beside Yuan Shao was kind to the nomads； and the two brothers have been more so。 They must be destroyed。 As for Liu Biao he is a mere gossip； who needs not cause the least anxiety。 And Liu Bei is unfit for any heavy responsibility and will take no trouble over a light one。 You may leave the base with perfect safety and make as long an expedition as you choose。 Nothing will happen。〃
〃You speak well； O Guo Jia；〃 said Cao Cao。
He led his legions； heavy and light； to the edge of the desert； with many wagons。 The expedition marched into the Gobi Desert。 The rolling ocean of yellow sand spread its waves before them； and they saw far and near the eddying sand pillars； and felt the fierce winds that drove them forward。 The road became precipitous and progress difficult。 Cao Cao began to think of returning and spoke thereof to Guo Jia； who had advised the journey。
Guo Jia had speedily fallen victim to the effects of the climate； and at this time he lay in his cart very ill。
Cao Cao's tears fell as he said； 〃My friend； you are suffering for my ambition to subdue the Gobi Desert。 I cannot bear to think you should be ill。〃
〃You have always been very good to me；〃 said the sick man； 〃and I can never repay what I owe you。〃
〃The country is exceedingly precipitous； and I am thinking of going back。 What think you？〃
Guo Jia replied； 〃The success of an expedition of this kind depends upon celerity。 To strike a sudden blow on a distant spot with a heavy baggage train is difficult。 To ensure success the need is light troops and a good road to strike quickly before an enemy has time to prepare。 Now you must find guides who know the road well。〃
Then the sick adviser was left at Yezhou for treatment； and they sought among the natives for some persons to serve as guides。 Tian Chou； one of Yuan Shao's old generals； knew those parts well； and Cao Cao called him and questioned him。
Tian Chou said； 〃Between autumn and summer this route is under water； the shallow places too heavy for wheeled traffic； the deep parts insufficient for boats。 It is always difficult。 Therefore you would do better to return and at Lulong cross the Baitan Pass into the desert。 Then advance to Liucheng and smite before there is time to prepare。 One sudden rush will settle King Mao Dun。〃
For this valuable information and plan； Tian Chou was made General Who Calms the North； and went in advance as leader and guide。 Next after him came Zhang Liao； and Cao Cao brought up the rear。 They advanced by double marches。
Tian Chou led Zhang Liao to White Wolf Hills； where they came upon Yuan Xi； Yuan Shang； and King Mao Dun and a force of ten thousand cavalry。 Zhang Liao galloped to inform his chief； and Cao Cao rode up to the top of an eminence to survey the foe。 He saw a large mass of cavalry without any military formation advancing in a disorderly crowd。
Said he； 〃They have no formation。 We can easily rout them。〃
Then he handed over his ensign of mand to Zhang Liao who； with Xu Chu； Yu Jin； and Xu Huang； made a vigorous attack from four different points； with the result that the enemy was thrown into confusion。 Zhang Liao rode forward and slew King Mao Dun； and the other generals gave in。 Yuan Xi and Yuan Shang with a few thousand of horse got away east into Liaodong。
Cao Cao then led his army into Liucheng。 For his services； Tian Chou was conferred the rank of Lord of Liucheng and mander of that county。
But Tian Chou declined the rank； saying with tears； 〃I am a renegade and a fugitive。 It is my good fortune that you spared my life； and how can I accept a rank for betraying Lulong？ I would rather die than accept the lordship。〃
Cao Cao recognized that reason was on Tian Chou's side and conferred upon him the office of Court Counselor。 Cao Cao then pacified the Xiongnu Chieftains； collected a large number of horses； and at once set out on the homeward march。