Deng Ai was still on the Qishan Mountains training the Wei soldiers when he heard that the Shu armies were once more on the war path. He called his officers together.
And Military Adviser Wang Guan said, “I have a plan to propose, but I will not tell it openly. However, I have written it down for your consideration.”
Deng Ai took the envelop, opened, and read it.
“Though excellent, I fear it is not enough to beguile the leader of Shu,” said Deng Ai as he finished reading.
“I am willing to stake my life on it,” said Wang Guan, “and I will lead the way.”
“Since you have such confidence you may try. You ought certainly to succeed.”
So five thousand troops were put under the leadership of Wang Guan, and they set out for the Xie Valley, where they fell in with the scouts of Jiang Wei's force.
Seeing these, their leader, Wang Guan, shouted, “We are deserters: tell your leader.”
So the scouts told Jiang Wei, who replied, “Hold up the soldiers, letting their leader only come to me.”
Wang Guan went forward and kneeled before Jiang Wei, saying, “I am a nephew of Wang Jing, and I hate Sima Zhao for what he has done to the Emperor and my family, and I wish to join you and my five thousand soldiers with me. I also desire to be sent against the rebel crew that I may avenge my uncle.”
Then said Jiang Wei, “Since you are sincere in your desertion, I must be sincere in my treatment of you. The one thing my army needs is grain. There is plenty at the border of the Lands of Rivers; and if you can transport it to Qishan, I can go straightway and take the Qishan camps of Deng Ai.”
This reply rejoiced Wang Guan, who saw that Jiang Wei was just going to walk into the trap. So he agreed at once.
“But you will not need five thousand troops to see after the transport. Take three thousand and leave two thousand as guides for me.”
Wang Guan, thinking that suspicions would be raised if he refused, took the three thousand of his troops and marched away, and the other two thousand were attached to the army of Shu.
Then Xiahou Ba was announced, and, when he was come in, he said, “O Commander, why have you believed the tale of this Wang Guan? In Wei I never heard that Wang Guan was related to Wang Jing, though it is true I never made particular inquiries. You should look to it, for there is much pretense in his story.”
“I know Wang Guan is false,” said Jiang Wei, with a smile. “That is why I have taken away many of his force. I am meeting trick with trick.”
“How do you know for certain he is a false?”
“Sima Zhao is as crafty as Cao Cao. If he slew all Wang Jing's family, would he have left a nephew and sent that nephew to the pass beyond his own reach with soldiers? You saw this, as did I.”
So Jiang Wei did not go out by the Xie Valley, but he set an ambush there ready for any move of Wang Guan. And indeed, within ten days, the ambush caught a man with a letter from Wang Guan to Deng Ai telling him what had come about. From the letter and the bearer thereof, Jiang Wei learned that Wang Guan
would divert a convoy of grain to the Wei camps on the twentieth and Deng Ai was to send troops to Yunshan Valley to help.
Jiang Wei beheaded the courier. Then he sent another letter to Deng Ai by a man dressed as a Wei soldier, the date being altered to the fifteenth instead of the twentieth.
As a preparation, Jiang Wei ordered many wagons to be emptied of their grain and laden with inflammables, covered with green cloth. The two thousand Wei soldiers were ordered to show flags belonging to the Shu transport corps. Then Jiang Wei and Xiahou Ba went into the valleys in ambush, while Jiang Shu was ordered to march to the Xie Valley, and Liao Hua and Zhang Yi were sent to capture Qishan.
The letter, apparently from Wang Guan, was sufficient for Deng Ai, and he wrote back to say it was agreed. So on the fifteenth day, Deng Ai led out fifty thousand veteran troops and moved in sight near Yunshan Valley. And the scouts saw endless carts of grain and fodder in the distance zigzagging through the mountains. When Deng Ai got closer, he distinguished the uniforms of Wei.
His staff urged him, saying, “It is getting dark; O General, hurry to help Wang Guan escort the convoy out of the valley.”
“The mountains ahead are hazardous,” said the general. “If by any chance an ambush has been laid, we could hardly escape. We will wait here.”
But just then two horsemen came up at a gallop and said, “Just as General Wang Guan was crossing the frontier with the convoy, he was pursued, and reinforcements are urgently needed.”
Deng Ai, realizing the importance of the request, gave orders to press onward. It was the first watch, and a full moon was shining as bright as day. Shouting was heard behind the hills, and he could only conclude it was the noise of the battle in which Wang Guan was engaged.
So Deng Ai dashed over the hills. But suddenly a body of troops came out from the shelter of a grove of trees, and at their head rode the Shu leader, Fu Qian.
“Deng Ai, you are stupid! You have just fallen into the trap set for you by our general. Dismount and prepare for death!”
Deng Ai halted and turned to flee. Then the wagons burst into flame. That flame was a signal, and down came the army of Shu. He heard shouts all round him, “A thousand ounces of gold for anyone who captures Deng Ai, and a lordship of ten thousand households as well!”
Terrified, Deng Ai dropped his arms, threw aside his armor, slipped from his steed, mingled with the footmen, and with them scrambled up the hills. The generals of Shu only looked for him among the mounted leaders, never guessing that he had got away among the common soldiers. So he was not captured.
Jiang Wei gathered in his victorious army and went to meet Wang Guan and his convoy.
Having made all arrangements, as he thought, complete, Wang Guan was patiently awaiting the development of his scheme, when a trusted subordinate came and told him that the ruse had been discovered and Deng Ai had already suffered defeat. Wang Guan sent out some scouts, and the report was confirmed, with the addition that the Shu armies were coming against him. Moreover, clouds of dust were rising. There was no way of escape, so Wang Guan ordered his troops to set fire to the convoy, and soon huge flames were rising high into the air.
“The case is desperate,” cried Wang Guan. “It is a fight to the death!”
He led his force westward, but the army of Shu came in pursuit. Jiang Wei thought Wang Guan would try at all costs to get back to his own side, but instead, Wang Guan went on toward Hanzhong; and as his troops were too few to risk a battle, Wang Guan ordered them to burn and destroy all military stations and even the Plank Trail as he went. Fearing the loss of Hanzhong, Jiang Wei made all haste along the by-roads after Wang Guan. Surrounded on all sides, Wang Guan jumped into the Black Dragon River and so died. Those of his soldiers who survived were slain by Jiang Wei.
Though a victory had been won and Wang Guan killed, it was costly. Many wagons and much grain had been lost, and the Plank Trail had been destroyed. Jiang Wei led his army into Hanzhong.
Deng Ai made his way back to Qishan. From there he reported his defeat to the Ruler of Wei and asked for degradation as a penalty. However, Sima Zhao saw that Deng Ai had rendered good services, so he did not degrade the general, but, on the other hand, sent him magnificent gifts, which Deng Ai distributed to the families of the soldiers who had been killed. Sima Zhao also sent him fifty thousand troops as reinforcement lest Shu should attack again.
Jiang Wei set about the restoration of the Plank Trail ready for the next expedition.
Repair the roads for marching feet to tread,