The Yi (Chinese 彝, formerly also known as the Lolo - now considered perjorative- or Wuman. They often refer to themselves as 'Nuosu' in their own language) are the largest non-Han ethnic group in southwest China (6,578,524 people recorded in the 1990 census), the seventh most numerous ethnic group in China (after the Han, Zhuang, Manchu, Hui, Miao, and Uighur).

Ethnographers classify anything between six and twenty mutually unintelligible distinct dialects under the broad family of Yi, a Tibeto-Burman language. This reflects the wide geographic distribution of centres of Yi population, with some three million, or about two thirds of the total Yi population, living in Yunnan; a further one million in Sichuan (concentrated in the Great Liangshan mountains, the largest single Yi community in China), and smaller groups in northwest Guizhou (about half a million people) and northern Guangxi (several thousand Yi people). The Yi language group includes Lisu, Naxi, Hani, Lahu and Bai, although these latter peoples are considered to be separate nationalities in China.

The Yi developed their own script around 13th century AD. The standardised written form of Yi developed in recent times has eight hundred or so characters. There exists a body of historical, medical, literary and genealogical works in the pre-reformed version of the script, and a number of inscriptions and stele survive to the present day. The also devised their own solar calendar which divided the year into ten months, though the use of the Chinese lunar calendar came to replace it over the years.

The Yi were traditonally animists, worshiping spirits in the landscape that surrounded them. Wise men, shamans called 'Bimou' - a Yi word denoting literacy - could mediate relations with the spirit world through ceremonial possession, and perfomed healing rituals and blessing of the crops The role of Bimou was hereditary. They are still to be found in most Yi villages today.

Yi people, living for the most part in high mountain areas, traditionally practised swidden farming, with buckwheat, oats, potatoes and maize as staple crops. They were also herders and hunters, and where possible paddy rice was farmed. The widely varying altitude and geography of the places where the Yi live naturally affect the crop mix.

From early times Yi society was divided by caste, with a small group (about 5% of the population) known as the 'Black Bone' holding land and power, and preserving their bloodline by marrying exclusively within their own caste. A larger caste (about 50% of the population) known as the 'White Bone' lived as serfs, able to own some property but tied to a Black Bone overlord and obliged to provide corvée labour to their masters. There was also a substantial "slave" caste (this terminology is disputed in some recent anthroplogical works), often captured Han Chinese or their descendants, who were the property of either Black or White Bone masters. This social order had largely died out in Yunnan and Guizhou, but survived until the 1950s in the mountain fastness of the Greater Liangshan in Sichuan.

Early Chinese historical sources held that the Yi people were related to the Qiang and Di nationalities. The earliest records (between the 2nd century BC and the first century AD) place the centres of the Yi around the areas of Dianchi in Yunnan and Qiongdou in Sichuan. The Yi spread into northeast and southern Yunnan, northwest Guizhou and northwestern Guangxi after the 3rd century AD. They were the principle ethnic group in the kingdom of Nanzhao, which flourished from the eighth century until superseded by the kingdom of Dali in 937. This lasted until conquered by the Yuan Dynasty in the 13th century, when the Yi came under the vassalage of the Chinese empire, ruled through local headmen whose subjugation to central authority varied over time and with geography. Large numbers of Han migrants also began to move into traditional Yi areas around this time, leaving only the high mountain areas comparatively free of direct Han influence.

The annual "Torch Festival," (huo ba jie) held around 24th of the sixth lunar month, is a celebration common to Yi people in most areas of the country. Villagers carry blazing torches around their houses and fields in a symbolic purification. Then celebrations, music and dancing around large bonfires express the collective hopes for a good harvest. The event can last a number of days, and in some areas includes horse racing, bull fighting and sporting contests. The 'International Torch Festival' in Xichang has become a fixture of the tourist calendar and draws visitors from across China and beyond.

After 1949, in line with the new nationalities policy, the central government established Yi autonomous prefectures in Liangshan in Sichuan, and Chuxiong and Honghe (Hani and Yi) in Yunnan. Autonomous counties, either exclusively Yi or combined with other ethnic groups were established in Yunnan's Eshan, Lunan, Ninglang, Weishan, Jiangcheng, Nanjian, Xundian, Xinping and Yuanjiang, Guizhou's Weining and Longlin of Guangxi.

The 'democratic reforms' carried out between 1956 and 1958 saw the redistribution of 120,000 hectares of land in Liangshan alone and the freeing of 690,000 slaves. Infrastructure investment brought the first paved roads to Liangshan in 1952, and the Kunming-Chengdu railway now passes through the region. A measure of industrialisation has followed. Xichang is now one of the centres of the Chinese aerospace industry, and it is from here that the Long March rockets have been launched