Hills Clan (Civ6)/Civilopedia

In the spur of the Himalayas lying within present-day Burma, Laos and neighboring countries, local kingdoms often divided people into two categories – hill and valley. Valley people – Shan, Thai, Burmese, or Lao – grew rice, were Buddhist, and were subject to the rule of the king. But highland people – the Akha, Hmong, Mien, or Kachin – were animist, grew root crops, and existed under their own, largely egalitarian, law. These divisions marked political, religious, and economic worlds, but they were also porous. Lowlanders fleeing a repressive king might flee to the hills, while highlanders attracted by urban life might descend.
At times, these relationships were peaceful, and these groups traded openly – salt and silver from the hills; manufactured goods from the lowlands. But this peace was fragile. Lowland states would raid highland groups (something which the fact that the Laotian word for highland people - kha - was a synonym for "slave" attests), or highlanders might decide they didn’t want to trade for lowland goods and go on raids to get what they wanted. Some of these highland groups cultivated a fearsome reputation. The Wa of Burma, for instance, kept the heads of their enemies posted outside of their villages, not only showing the prowess of Wa warriors, but also enlisting – so the story went – the spirits of the dead in guarding the village. Over time, these highland groups became political actors in their own right, as they were courted by, at different times, British (in the colonial period) and American (in the Cold War) forces in attempts to find allies against lowland states in their own quests for domination.