Tinku is a form of ritual conflict practiced by local people in Potosí, Bolivia.
Tinkus occur "between different communities, moieties, or kin groups." They are prearranged and usually take place in the small towns of southern Bolivia. Tinkus are very festive, with an audience of men, women, and children, who bring food and drink. Alcohol is also brought and sold along with food during the tinku.
The tinkus can become very violent, and people do get injured and even die. But, the deaths can be seen as good omens for good harvests.
Tinkus have been a tradition of Andean culture since before they first had contact with Europeans. Some anthropologists hypothesize that Ancient Andes culture would have tinkus instead of battles. This would help curb aggression between different groups, and allow for entertainment, similar to football games in the United States. There are some anthropologists that believe the tradition of the Tinku dates back to the time of the Moche culture, where neighboring tribes would annually fight one another.
Taken from the Wikipedia entry on Tinku.
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