The three back palaces of the Palace Museum usually refer to the Qianqing Palace, Jiaotai Palace, and Kunning Palace in the inner court. It is located on the central axis behind the three front halls. It is the core of the inner court building complex. Surrounded by gates and verandas, it covers an area of ​​26,000 square meters and has more than 420 houses. In front of it is the Qianqing Gate, the inner palace gate. On the 2-meter-high platform inside the gate are the Qianqing Palace, Jiaotai Palace, and Kunning Palace from south to north. The Qianqing Palace was the emperor’s residence in the Ming Dynasty. The Qing Dynasty followed the Ming system, and moved to the Yangxin Palace during Yongzheng’s reign. It was used as a place where the emperor summoned ministers, reviewed memorials, handled daily government affairs and held performances.