Liao Taizong, after taking the sixteen states of Yanyun, its territory includes a vast area south of the Great Wall, in order to maintain the economic life of the Khitan people's tradition of riding and shooting, still living "anytime, horses and carts for the home" of life. As recorded in the "History of Liao", "Liao country all desert, soak the Great Wall of the territory, according to the appropriate governance, autumn and winter against the cold, spring and summer to avoid the heat, with the water and grass on the land and fishing, the years as a rule", four times each line in the place, in this special economic, political and cultural context, in the management system of the Khitan, gradually formed a set of county has a distinctive nomadic ethnic groups of the Khitan The unique characteristics of the four times of the bowl system. Khitan Emperor four times tour of the Palace tent (also known as the tent), that is, the spring press bowl, summer press bowl, fall press bowl, winter press bowl.