At the court of Wei one of the ministers told the story of defeat of Cao Zhen and the allies, and asked the Ruler of Wei to decide upon the next step. Cao Rui was alarmed and asked for someone to say how to drive off the victorious foe.
Thereupon Hua Xin said, “It will be necessary for Your Majesty to go in person. You should call together all the nobles, and each will have to exert himself. Unless this is done, Capital Changan will be lost and the whole country be in danger.”
But Imperial Guardian Zhong Yao opposed him.
Said he, “The knowledge of every leader must exceed that of those led; then only will he be able to control them. Sun Zi the Strategist sums it up very briefly: 'Know the enemy, know thyself; and every battle is a victory.' I know Cao Zhen has had great experience in the field, but he is no match for Zhuge Liang. Still there is such a match, and I will pledge my whole family that he will succeed. But Your Majesty may be unwilling to listen to me.” The Ruler of Wei replied, “You are a minister of high rank and old. If you know any wise person able to repel these soldiers of Shu, call him without delay and ease my mind.”
Then said Zhong Yao, “When Zhuge Liang decided to invade us, he was afraid of the one man I will name. Wherefore he spread calumnies concerning him, raising suspicion in Your Majesty's mind that you might dismiss him. That done, Zhuge Liang invaded. Now employ this man again, and the enemy will retire.”
“Who is it?” asked the Ruler of Wei.
“I mean the Regent Marshal Sima Yi.”
“I have long regretted my action,” said Cao Rui. “Where now is friend Sima Yi?”
“He is at the city of Wancheng, idle.”
An edict was prepared recalling Sima Yi and restoring him to his rank and titles, and conferring upon him the new title Commander-in-Chief and General Who Pacifies the West. All troops of Nanyang were set in motion, and Cao Rui led them to Changan. At the same time Cao Rui ordered Sima Yi to be there to meet him on a certain day. And the orders were sent by a swift messenger to the city of Wancheng.
At this time Zhuge Liang greatly rejoiced at the success he had had. He was at Qishan, busy with plans for other victories, when Li Yan, who was in command at the Palace of Eternal Peace, sent his son Li Feng to the camp. Zhuge Liang concluded that such a visit could only mean that Wu had invaded them, and he was in consequence cast down. However, he summoned Li Feng to his tent, and when asked the object of his mission, Li Feng replied that he had joyful news to impart.
“What is your joyful news?” said Zhuge Liang.
“Formerly Meng Da deserted to Wei, but only because he could do nothing else. Cao Pi thought much of his capabilities, treated him most generously, kept him at his side, gave him titles of General Who Establishes Strong Arms and Lord of Pingyang, and appointed him to the posts of Governor of Xincheng and Commander of Shangyong and Jincheng, and so on. But when Cao Pi died, all was changed. In Cao Rui's court were many who were jealous of Meng Da's influence and power, so that he enjoyed no peace.
“He used to talk about being originally one of the Shu leaders, and he was forced to do so-and-so. Lately he has sent several confidants with letters to my father asking that he would state his case to you as to the happenings when the five armies came upon Shu. Now he is at Xincheng, and, hearing you are attacking Wei, he proposes to lead the army of the three counties about Xincheng, Jincheng, and Shangyong to attack Luoyang while you attack Changan, whereby both capitals will be taken. I have brought with me his messenger and his letters.”
This was good news, and the bearer was fittingly rewarded. But at that moment came the news that Cao Rui was leading an army to Changan and had recalled the banished Sima Yi to office. This piece of bad news saddened Zhuge Liang not a little.
He told Ma Su, who said, “Cao Rui should not be your worry. If he goes to Changan, we will march there and capture him on the road, and there will be an end of him.”
“Do you think I fear him?” said Zhuge Liang bitterly. “But the recall of Sima Yi is another matter; that troubles me. And Meng Da's proposal will avail nothing if he comes across this man. Meng Da is no match for him. He will he captured, and, if he should be, the Middle Land will be hard to conquer.” “Why not put Meng Da on his guard then?” said Ma Su.
Zhuge Liang decided to write, and the letter was dispatched immediately.
Meng Da was then at Xincheng, anxiously expecting the return of his last confidential messenger, when, one day, the man returned and gave him this letter from Zhuge Liang himself:
