Why do Chinese epics circulate mainly in the southwest and northwest of China?

For Chinese scholars, the strict sense of epic is the classical form of heroic epic. Because the epic can only be produced in the childhood of human history, it excludes from the epic some of the narrative poems that were produced later in the class society to glorify the heroes. Chinese epic scholars have done a lot of research on the origin, formation and development of epics, but the biggest harvest is only some generalized conclusions --- epics were produced in the childhood age of mankind, or the heroic age. Epic poetry can be divided into two main categories, the epic of creation and the heroic epic. Creation epics, also known as "primitive" epics or mythological epics. The different "Genesis" of the Naxi, Yao and Bai tribes in China, the "Meiguo" and "Song of the A Thin People" of the Yi tribe, and the "Ancient Songs of the Miao Tribe" all belong to this type of epics. The contents of these works are basically the same, mainly recounting the formation of the heaven and earth, the sun and the moon, the emergence of mankind, the origin of domestic animals and various crops, and the life of people in the early society as envisioned and remembered by the ancient people. Heroic epics are epics with stories of national heroes' struggles as the main theme. It was created in what Engels called the "military democracy" and the "heroic age", when the power of clans and tribes grew strong enough to form a confrontation with nature and alien enemies. The three major epics of China's ethnic minorities are included in the scope of heroic epics. The minorities of northern and southern China have a long tradition of epic poetry. However, in the absence of early written texts in China, the epics were basically passed down orally among the people of the remote ethnic minorities of China. Therefore, the living form of oral transmission is a major characteristic of Chinese epic. Secondly, due to the imbalance of the historical development of each ethnic group, the epic poems of each ethnic group show diversified and multi-layered contents of cultural history. Early epic poems are closely related to creation myths and primitive beliefs, and the epic poems about clan vengeance, tribal wars and national migrations are also connected with secularized hero worship, which show the characteristics of heroic poems. After some ethnic groups have entered the modern society, new epics are still being produced. Thirdly, there are various types of epic poems of different ethnic groups in China. The northern ethnic groups, such as the Mongols, Tibetans, Viennese, Hakkas and Kirgizians, are famous for their long heroic epic poems, while the epics of the Dai, Yi, Miao and Zhuang in the south are mostly small and medium-sized ancient songs. Scholars have been studying the origins of these epics, their various forms of transmission, text types, their artistic characteristics, cultural roots, and influence on later literature. Most of the epics in China were discovered after the 1950s, and it is only in the last 30 years that epics have been collected, recorded, translated, organized, and published. The study of epics in China started even later, with more systematic research beginning in the mid-1980s. Chinese academics recognized epic as a folk art style after 1949. This was mainly due to the influence of Marxist concepts of aesthetics and literature, and after the 1980s, scholars began to study epic as a style of folklore, with the anthropological school being the most influential. After the mid-1990s, scholars began to establish the concept of "living form" of epics, which was regarded as the oral tradition of Chinese minority epics. There is a large number of epics in ancient Chinese literature, mainly distributed in the northwest, southwest and northeast regions, especially in minority cultures. Among them, "Gesar" of Tibetans, "Jangal" of Mongols and "Manas" of Kirghiz have become the "three major traditional epics in China", and they are all "living epics" inherited to this day. In addition, there are countless other epic traditions in Southwest China that have been preserved to this day.