Knotty puzzle
New insights into the conundrum of the Inca khipu.

The Inca civilization of Peru reached the height of its power during the 15th and 16th centuries AD. Its empire, Tawantinsuyu, ‘the Land of the Four Quarters’, was a jigsaw of highways and village paths traversed by people and llama caravans. It was coordinated by an army of officials, who maintained intricate records of the people and products of the Inca’s domains. The hundreds of functionaries behind the empire depended on records maintained on khipus, knotted strings. They left no written records behind them, just enigmatic cords adorned with knots of different sizes and colours. There is a mere handful of surviving indigenous Inca histories except for chronicles written by the Spanish.
Scholars have puzzled over the knotted khipu textiles for generations, and they now have a general sense of what they represented. Many were clearly census data. Others were calendar systems of inventories of goods. Any cultural information they held was a mystery.
Anthropologist Gary Urton created a Khipu Database at Harvard University, which contained more than 900 examples. When Urton examined six 17th-century khipus from northwestern Peru, he happened to pick up a Spanish census document of the same age and from the same region with numbers that matched those in the khipus.
By chance, student Manny Medrano, was sitting in in a class where Urton mentioned the find. Thanks to Medrano’s skill with numbers from his economic major, he discovered that the ways in which the cords were tied onto a khipu corresponded with the social status of many of the 132 people in the census document. The colours appeared to be related to peoples’ first names. This major breakthrough, just published, throws light on the social organization of people counted in the census. This may be a key for deciphering numerous other strings in the data base.
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Image: An Inca khipu held by the Larco Museum, Lima, Peru.