Yu is the most famous imperial army in ancient China with a long history. Feather forest, from the Western Han Dynasty, was originally named "Zhang Jian Qi Ying", named after guarding Zhang Jian Palace, and later changed to feather forest, which means "wing of the country, like the glory of the forest". "Hanshu" said: "In the first year of Liang Wudi, Zhang Jianying Riding was first set up, and later it was renamed Yulin Riding, and it belonged to Guang Luxun. He also took in descendants who died in the army, raised feather forest officials and taught five soldiers to be orphans in feather forest. " In other words, Yu is the praetorian guard under Guang Luxun. During the Western Han Dynasty, there were about 2,000 Qi and orphans. Yulin, as the emperor's guard and etiquette troops, has a higher status than other troops, and the soldiers are all professional soldiers and aristocratic soldiers.

In the early years of Hongwu in the Ming Dynasty, the Guards officially appeared. Kingsguard, as its name implies, is a special army guarding the emperor, the royal family and the imperial city. In feudal society, the emperor's will was called "imperial decree", the emperor's seal was called "imperial seal" and the emperor's expedition was called "personal expedition", so the army guarding the emperor became the "body guard". Being stationed in the capital is another important feature of the Kingsguard. In this period, the feather guard and the forbidden guard existed at the same time, but the position of the forbidden guard was much higher than that of the feather guard, which was almost the same as that of the Han and Tang Dynasties. After the Ming dynasty, there was no feather forest army.