On 14 April 1947, communist forces launched their second-stage offensive by taking Niangzi (娘子) Pass and Jingin (井陉). Important nationalist strongholds to the north of Yangquan including White Earth Slope (Baitupo, 白土坡), Upper Yinying (Shangyinying 上荫莹), and Lower Yinying (Xiayinying, 下荫莹) subsequently fell in a domino effect. After losing nearly four dozen local strongholds, Pingding County and Yangquan were both seriously threatened by the communists, who besieged the last two remaining nationalist strongholds on 25 April 1947. On 24 April 1947, Yan Xishan ordered the nationalist 33rd Army stationed in Taiyuan and Qi (祁) County eastward to reinforce the local nationalist garrison via railway, and reached Yangquan the next day. The defense of Yangquan was further enhanced by the arrival of the nationalist 8th and 10th Division on 28 April 1947. In response, the communists redeployed part of their force to the west to surround the nationalists by taking regions including Qinquan (芹泉), Yu (盂) County, and Ceshiyi (测石驿), thus completely sealing off the retreating routes of the nationalist reinforcement. On 29 April 1947, the main force of the nationalist 33rd Army retreated westward, but they were stopped by the communist forces at the Ceshiyi (测石驿) region.