Public Release: 

Inka textile devices served as business ledgers

Computer analysis reveals numerical and other patterns in knotted objects

National Science Foundation

While most ancient cultures recorded civil matters and business transactions by inscribing characters on 2-dimensional sheets, new evidence shows Peru's original inhabitants used a 3-dimensional system of knotted strings to keep track of things.

In the Aug. 12 edition of the journal Science, Harvard University anthropologist Gary Urton and database developer Carrie Brezine say their computer analysis of 21 of the knotted objects, known as "khipu," revealed distinct patterns that help confirm the textile devices were used for record keeping and to communicate affairs of state throughout the sprawling empire of the Inka--a spelling Urton prefers because it is closer to the native Peruvian language.

Seven of the objects appeared to contain cumulative numerical data.

Deciphering the khipu information also helps explain how the vast Inka bureaucracy, which ruled the Andes from 1425 to 1532, stayed so organized without ever developing a system of 2-dimensional writing.

According to Urton, khipu were used "to record the information deemed most important to the state, which often included accounting and other data related to censuses, finance and the military. In this regard," he said, 'the discovery that khipu were used as ledger books reveals a new consonance between the Inka and other ancient cultures."


The work was supported by the National Science Foundation's behavioral and cognitive sciences program, the Dumbarton Oaks Foundation, Harvard's Faculty of Arts and Sciences and the John D. and Catherine T. MacArthur Foundation.

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