Yangshao culture was named after being discovered in Yangshao village, Mianchi county, Henan province in 1921. Dating back to 5,000 to 7,000 years ago, Yangshao culture existed extensively along the middle and lower reaches of the Yellow River, with Henan province as its core area. Yangshao culture marks a significant transition from an equal society to hierarchical one. Central settlements, hierarchical settlements distributed around central settlements, and earth defenses that encircled central cities that required the method of stamping earth between board frames, all signal a dramatic shift in the social structure that occurred during that period and reveal the important status of Henan province in the formation of Chinese civilization.