Introduction to Yikun Palace: In the middle of the West Sixth Palace area, it was also known as Wan'an Palace in the Ming Dynasty. Zheng Guifei, the favorite of Emperor Wanli, once lived in this palace. In the late Qing Dynasty, the back hall of Yikun Palace and the gate of Chuxiu Palace were demolished and rebuilt into the main body and the Harmony Hall, which became the front hall of the Chuxiu Palace courtyard.