De first floor introduction: In the northeast corner of the backyard of the Dudu Mansion, there is also a small courtyard. In the courtyard stands the second high-rise building of Yan Mansion - De first floor. The front of this building can be connected to the Dudu's Mansion, and the rear is connected to the second courtyard of the East Garden through a tunnel. Because Yan Xishan was named a first-class marquis by Yuan Shikai, he named it "Deyilou" based on the meaning of Laozi's "Tao Te Ching", "The sky is clear, the earth is peaceful, and man is holy" To commemorate.