Ancient Incan accounting tool a Gordian knot
Researchers hope trove of new cords will help decode any non-numerical meanings
LIMA, PERU— In a dry canyon strewn with the ruins of a long-dead city, archeologists have made a discovery they hope will help unravel one of the most tenacious mysteries of ancient Peru: how to read the knotted string records, known as khipus, kept by the Incas.
At the site called Incahuasi, about 160 kilometres south of Lima, excavators have found, for the first time, several khipus in the place where they were used — in this case, a storage house for agricultural products where they appear to have been used as accounting books to record the amount of peanuts, chili peppers, beans, corn and other items that went in and out.
In some cases the khipus — the first ones were found at the site in 2013 — were buried under the remnants of centuries-old produce, which was preserved thanks to the extremely dry desert conditions.
That was a blockbuster discovery because archeologists had previously found khipus only in graves, where they were often buried with the scribes who created and used the devices. Many others are in the possession of collectors or museums, stripped of information relating to their provenance.
Khipus are made of a series of cotton or wool strings hanging from a main cord. Each string may have several knots, with the type and location of the knot conveying meaning. The colour of the strands used to make the string and the way the strands are twisted together may also be part of the khipus’ system of storing and relaying information.
Researchers have long had a basic understanding of the numerical system incorporated in the khipus, where knots represent numbers and the relation between knots and strings can represent mathematical operations, like addition and subtraction.
But researchers have been unable to identify the meaning of any possible non-numerical signifiers in khipus, and as a result they cannot read any non-mathematical words or phrases.
Now, the Incahuasi researchers hope that by studying the khipus and comparing them with others in a large database, they may find that the khipus discovered with the peanuts contain a colour, knot or other signifier for “peanut.” The same goes for those found with chili peppers, beans and corn.
“We can look at how the chili pepper khipu differs from the peanut khipu and from the corn khipu in terms of their colour and other characteristics and we can build up a kind of sign vocabulary of how they were signifying this or that thing in their world,” said Gary Urton, a leading expert on khipus who is studying the new trove with Alejandro Chu, the archeologist who led the excavation.
“It’s not the great Rosetta Stone but it’s quite an important new body of data to work with,” he said, adding, “It’s tremendously exciting.”
For now, the 29 khipus from In- cahuasi, which are about 500 years old, are kept in an unassuming brick house in a residential neighbourhood in Lima, along with a scattering of artifacts from other excavations, including two mummies (of a child and a dog), some bags of human bones, dozens of fragile textiles rolled up between layers of paper, and numerous pots meticulously reassembled from shards.
The house belongs to Patricia Landa, an archeological conservator, who also keeps a menagerie of cats and dogs, including three hairless Peruvian dogs of the kind once raised by the Incas for food.
It is Landa who takes the Incahuasi khipus, some of which were found neatly rolled up and others in snarled jumbles, and painstakingly cleans and untangles them and prepares them for researchers to decipher.
“You have a very special relationship with the material,” Landa, 59, said. “I talk to them. I say, ‘Excuse me for disturbing your rest but you’re helping us to understand your ancestors.’ ”
Incahuasi, which means “house of the Inca emperor,” was a city used in the late 15th and early 16th centuries as the base of operations for the Inca invasion of Peru’s southern coast, after which it became a thriving administrative centre, according to Chu, the archeologist. It sat in the arid hills above the green valley of the Canete River.
“There was probably lots of movement, with llama caravans bringing in farm produce,” he said.
The storehouse where the khipus were found was probably used to keep food needed to maintain the large number of troops deployed in the invasion.
The khipus found at Incahuasi appear to be all about counting beans, literally. But colonial-era documents suggest that khipus had many uses in both the pre-Hispanic and colonial period that went beyond accounting, including to keep calendrical information and to tell historical narratives.
Colonial records show that in some cases, such as land disputes, indigenous litigants would bring khipus to court and use them to explain or justify claims of land ownership, Chu said. He said that scribes would read the khipus and a court clerk would enter the information into the trial record.
Urton has created a database of all known khipus, about 870 of them, with detailed information on twothirds of them, recording their configurations, colours, numerical values and other information.
Because the Incahuasi khipus appear to be relatively simple inventories of agricultural products, it may be easier to decipher them than the more complex khipus that record historical information, Chu said.
And a breakthrough in deciphering the Incahuasi khipus could be a first step in reading more complex versions.
“If we can find the connection between the khipu and the product that it was found with we can contribute to the deciphering of the khipus,” Chu said.
Urton said the difference between the accounting khipus at Incahuasi and more elaborate khipus, “is the difference between, let’s say, your tax form and a novel.”
But they may also have key similarities: “They both use the same language, they both use the same numbers when they use numbers, and it’s in the same writing system.”