 However, Meng Da's rebellion plot was leaked out by Shen Yi (), the Administrator of Weixing (), whom Meng Da had a feud with.The Wei general Sima Yi wrote letters to Meng Da to put the latter in a dilemma on whether to rebel or not, and secretly led an army from Wan (in present-day Nanyang, Henan) to attack Meng Da's base in Xincheng.Sima Yi's forces arrived at Xincheng in just eight days and caught Meng Da completely off guard.