中国人民解放军第四野战军
After the fall of Tianjin to Communist forces on 14–15 January 1949, the Nationalist garrison in Beiping was effectively isolated. Fu Zuoyi came to the decision to negotiate a peace settlement on 21 January. In the following week, 260,000 Nationalist troops began to exit the city in anticipation of the immediate surrender. On 31 January 1949, the Fourth Field Army entered Beiping to take over the city which marked the conclusion of the Pingjin Campaign.