There have been four major walls:
208 BC (the Qin Dynasty)
1st century BC (the Han Dynasty)
1138 - 1198 (the Five Dynasties and Ten Kingdoms Period)
1368-1620 (from Hongwu Emperor until Wanli Emperor of the Ming Dynasty)
The Chinese were already familiar with the techniques of wall-building by the time of the Spring and Autumn Period, which began around the 7th century BC. During the Warring States Period from the 5th century BC to 221 BC, the states of Qi, Yan and Zhao all constructed extensive fortifications to defend their own borders. Built to withstand the attack of small arms such as swords and spears, these walls were made mostly by stamping earth and gravel between board frames.