They developed a force of light cavalry that could foray into the enemy territory to check on the enemy movements in his own grounds. They had many victories against the Xiongnu. They then employed renegade Xiongnu(匈奴Xiōngnú) horse masters to set up horse breeding stables and to train their troops in horsemanship. 

 

In 206 BC the first Han Dynasty(汉朝Hàncháo) was formed under the Gao Di Emperor, Liu Bang. At first he attempted to appease the northern invaders with gifts and increased trade but peace was off and on. A massive force of the Han army attacked the invaders and forced them back across the northern borders.

To consolidate their victories they began to mark out their new extended borders. In many areas they simply restored the old Qin wall. In order to build walls in the desert of the west, new methods of construction had to be devised. Here the soil consists of a gravel of sand and small stones. They used alternating layers of red willows and the gravel and lots of tamping. This produced a wall that has survived for some 2,000 years.

Using these techniques and hundreds of thousands of people, the Han were able to build the wall far into the Gobi desert. And where clay was used as a skin or coating it made the wall difficult to scale and protected it against the erosion of the weather. The Han leadership knew to have a strong frontier they not only needed to build a strong wall but they also needed crack troops to defend it.