ZHENGZHOU, Jan. 30 (Xinhua) -- A square that once served as military defense area in ancient China has been unearthed in the central Province of Henan.

Known as Wengcheng in Chinese, it is the earliest square defense area ever discovered in China, according to Liu Haiwang, head of the Henan Provincial Institute of Cultural Heritage and Archaeology.

The defense area was discovered in Henan's Kaifeng City, which once served as the capital of eight dynasties in China.

"The discovery provided valuable materials for research about the layout of the capital city of the Northern Song Dynasty (960-1127), the evolution of gates in ancient Chinese capitals and the history of Kaifeng's development," Liu said.

Wengcheng was usually built in military fortresses before the Tang Dynasty (618-907). It began to be part of city construction during the Song Dynasty (960-1279).