Wei was also a powerful State. After King Wei Wenhou succeeded to the throne, he put Likui, Leyang and great militarist Wuqi into important positions, which gradually made the state flourish. Wei later moved its capital Anyi, i.e. present Anyi County of Shanxi Province, to Daliang, now Kaifeng of Hennan.
Wei neighbored the Chu State on the southeast, taking present the Bianshui River as the boundary, the Song and Qi States on the east bounded by the Huaishui and Yingshui Rivers, the Han State on the south, the Qin State on the west bounded by North Luohe River and the Zhao State on the north.
Wei for years won wars upon the Qi, Chu, Song and Zhao States, but kept being defeated by the Qin State. While Qin took Wei as its serious trouble, Wei feared Qin. So Wei expanded the embankment of the Luoshui River near the west boundary and built it into a fortified wall. It ran more than 500 kilometers from south to north, starting from present Huxian County of Shannxi Province, going up the Luoshui River, passing through Fuxian, Suide, Mizhi County, crossing the Yellow River and finally arriving at present Guyang of Inner Mongolia. It was the West Wall of Wei. It is believed that King Wei Huiwang built this wall.
In a latest investigation over ancient walls, archeologists discovered some sites of the West Wall along a 300-kilometer route. The route started from Huanxian County of Shannxi Province, headed north and crossed the Weihe River, went on along the Luohe River, moved northeast and arrived at the west bank of the Yellow River of Hancheng County. The findings proved historical literatures of the West Wall route that set out from Huaxian County and headed north along the Luoshui River. Besides, a branch wall without mention in any material was discovered halfway on the exploitation. It branched out to the northeast and headed in the direction of Hancheng County.
In the late years of King Wei Huiwang, Wei was declining and kept losing wars to Qin, Chu, Qi and other states. To resist Qi and Qin, Wei built another wall near its capital Daliang. It was the South Wall of Wei. It can be inferred from literatures that this wall started from the place northwest to Old Yuanwu County of Henan Province, ran north and entered present Yuanyang County and then turned off the the southeast, went around to east Kaifeng, and headed westward till Mixian County. The length was about 200 kilometers.