The Dadiwan Site is located in the east of Nacun Village in Wuying Town, Qin'an County of Gansu Province.
Located about 45 kilometers from the county, the Dadiwan Site covers an area of over 360,000 square meters. The Gansu archaeological team carried out a six-year excavation project at the site from 1978 to the end of 1983, having unearthed over 200 house sites, 30 kilns and 8,000 pieces of cultural relics. According to the excavation data, Dadiwan is a site of the Neolithic Age that dates back 4,000 to 7,500 years ago.
Cultural relics found at the Dadiwan Site trace the development of manufacturing techniques as they evolved from the crude to the delicate. Early stone tools were simple, chipped implements, and only a select few were cut and polished. In the middle period, species and quantity increased along with technical development, resulting in cut and polished tools. In the late period, more complex and larger, more specialized and polished implements appeared, along with bone ware.
The technical development of pottery ware is more obvious. Among the unearthed pottery are red, gray and other ancient painted items made of clay pottery and sand pottery to form jars, pots, bottles, cups and wine vessels. Such items were painted with rope patterns and line shapes. Colored pottery includes such patterns as broad strips, arcs, triangles, stripes, fish, birds and geometric shapes composing dots, lines and arcs. Among the amaranth, black and white pieces, the round-bottomed pots with fish patterns and items embossed with three human figures are the most precious. The markings etched on a few wares provide new clues into the study of the origin of Chinese characters.
Most early house sites are half-pits that assume a round shape with a diameter of two to three meters, containing a small fireplace inside. Among the houses from the middle period are structures built on the ground besides half-pits with enlarged areas. In such houses the grounds were paved with small stones. During the late period, houses were mainly built on the ground and on a comparably large scale. The F405 House, for example, is about 14 meters in length and 11 meters wide, covering an area of about 150 square meters. It has a large room in the center and two small rooms on either side, with three doors open in each room. The remaining walls range from 0.1 to 0.9 meters in height. Over 100 wooden pillars were erected in the rooms, and 24 pillars stand near the walls for support. A huge kitchen ranging from 2.34 meters in diameter and 0.6 meters in height stands in the center of the hall. Its floor is smooth and solid with a thickness of 0.2 meters and paved with small stones mixed with earth. In another house, the floor contains charcoal drawings of human figures and animals.
The Dadiwan Site is rich in cultural relics and its layering of various cultures is clear and long-lasting. It is among the few Neolithic sites with a systemic chronicle sequence in east Gansu and the upper reaches of the Wei River, which plays a key role in archaeological study.