Meng Da
The "Jin Shu" account confirmed that Meng Da did have a feud with Shen Yi. Zhuge Liang planned to make use of this incident to lure Meng Da to defect to Shu sooner, so he sent Guo Mo (郭模) to feign surrender to Wei and divulge Meng's plan to Shen Yi. When Meng Da heard that the plot had been leaked out, he immediately made plans for a rebellion. Sima Yi, who was at Wan at that time, became worried that Meng Da would proceed with the revolt quickly, so he wrote a letter to Meng to calm him down. Sima Yi wrote, "General, you previously left Liu Bei and dedicated yourself to our state. Our state entrusted you with the duty of guarding the border and tasked you with planning an invasion on Shu. This is an obvious sign that our state trusts you. The people of Shu are fools and they hate you deeply. Zhuge Liang wants you back in Shu only because he has no other choice. What Guo Mo told Shen Yi is not a small issue. Why would Zhuge Liang so easily ask him to reveal your plot? This dangerous move is not difficult to comprehend." Meng Da was pleased when he received Sima Yi's letter, and he entered a dilemma on whether to rebel or not. During this time, Sima Yi secretly led his forces from Wan towards Xincheng. Sima Yi's subordinates suggested that they observe Meng Da's actions first before advancing, but Sima replied, "(Meng) Da is not a trustworthy person. Now that he is hesitating due to suspicions, we should seize this opportunity to get rid of him." Sima Yi's army then advanced quickly and reached Xincheng within eight days.