The Diyin Underground Courtyard is distributed in Sanmenxia City of Henan Province, Yuncheng City of Shanxi Province and Longdong District of Gansu Province, among which Sanmenxia City has the most complete preservation. Up to now, there are still more than 100 villages living in the underground courtyards.
Although the Diyin Underground Courtyard is a residential house, but before construction, need to know the Fengshui (geomancy) -- choose the terrain, the direction fo the main house, the size of courtyard and the auspicious day of construction; need to pay attention to adjusting measures of local conditions -- five elements, Yin and Yang coordination. The Balance of Yin and Yang is also needed between 3 main houses of a Diyin Underground Courtyard, they are the main house, the main entrance to the courtyard and the stove (kitchen).
Generally, a Diyin Underground Courtyard is about 30 meters long and 10 meters deep. The courtyard is dug from the ground. The main house is dug in the east of the courtyard which is usually 3 meter high; it is the cave dwelling for the home owner. The cave dwelling room for the elders in the family are in the middle, with one door and three windows; and the rooms for other families are on the sides, with one door and two windows. The kitchen cave dwelling is in the southeast, and the entrance is in the south; the cave dwelling rooms in the west and southwest are for the guests; the washroom is in the the northwest.
A circle of green bricks with eaves are usually lain around the underground courtyard and the ground, a 30-50 brick walls are built on it. The walls are used to prevent the ground rainwater from pouring into the underground courtyard, also for the safety of people working on the ground and the children playing on the ground, further more, for decoration. There are also drainage and leakage prevention facilities in the Diyin underground courtyard. For example, the base of the courtyard is reinforced with green bricks, the center of the courtyard is 30 cm lower than the surrounding cave dwelling house surrounding, and a water storage pit with 1 meter diameter is set at the corner of the courtyard, on which a stone slab covered and under which slag is laid for drainage and storage in case of rain.
There are three reasons why the local residents choose to build the Diyin Underground Courtyard :
1. The loess layer is 50-150 meters thick, the loess structure is hard-packed with earthquake and salt alkali resistance. And the underground water level is low, generally t he water level below 30 meters underground. These provide geological conditions for the underground courtyard construction.
2. The area is located in the continental monsoon area of the north temperate zone, with semi-arid climate, little rainfall and few heavy rain. And the temperature difference is big in four seasons, the cave dwelling house has the advantages of warm in winter and cool in summer.
3. economic reason. Since ancient times, both sides of the Yellow River in the area have been economic and cultural enter of China, with a large population and a relative lack of forest resources and coal resources; and folk house needed a lot of wood and brick, making brick needed wood and coal. So it was relatively difficult to build a house on the ground, that is why the local residents choose underground courtyard.
Now, with the living standard of local residents getting higher and higher, there are very few new underground courtyard built, and the new houses are all on the ground. This traditional Diyin Underground Courtyard have become a part of folk culture history.
