In the August 12, 2005 issue of Science magazine, Gary Urton and Carrie Brezine of the Khipu Database Project at Harvard University report their first successes at cracking the code of the ancient Incan accounting system known as the khipu. Urton and Brezine used computer analyses of a group of the knotted string objects from the Inca village of Puruchuco to begin deciphering the previously unreadable Incan records.
Incan Civilization and the Khipu
At its height around AD 1500, the Inca controlled almost all of the west coast of South America, from Ecuador to Chile. The Inca were an advanced civilization, and like every other advanced civilization on the planet, they had temples and priests and farming and ceramic production and irrigation systems and tribute collection and craft specialists. However, unlike every other civilization on the planet, the Inca did not have a writing system that we would recognize. This has always been somewhat of a puzzle: archaeologists assume that advanced civilizations must have some way of tracking what gets done, for the central administration to keep up on what went on in the far-flung pieces of its empire. Egypt had hieroglyphs on paper and stone; Mesopotamia had cuneiform pressed into clay; but what did the Inca have?
What the Inca had were khipu (sometimes spelled quipu), patterned collections of string, arranged by color (natural and dyed), fiber (cotton and llama/alpaca hair), twist (left- and right-hand), and knots of different sizes and lengths. A typical khipu consists of several twisted plaits of strings that descend from a single unifier string. Each descending plait has multiple knots, is twisted to the right or left, is dyed a different color, has multiple dyed threads in its plait. The pictures in the side bar illustrate this; and there are many other photos on the KBD website. Khipu are complicated, terrifically complicated, which led the Spanish clergy to burn them in mass quantities as things belonging to the devil.
The historian Garcilaso de la Vega, son of a Spanish conquistador and the niece of the Inca leader in the 16th century, reported that the khipu were record keeping tools, that were religiously kept in each village. Recent excavations at Caral suggest that khipu had been used by the Inca and their predecessors for some five thousand years. It seems a certainty that the khipu were the missing administrative records. But up until now, the khipu could not be confidently interpreted. A compilation of possible interpretations was published in 2002 in the edited book called Narrative Threads; but since testable hypotheses concerning any of these interpretations had not been determined, that was as far anyone could really take it.
Cracking the Khipu Code
Beginning in the fall of 2002, Gary Urton and Carrie Brezine began the Khipu Database Project, to collect information about the existing khipu and place coded data on color, fiber, and knot patterns into a computer database. The project, whose website is named Khipu Kamayuq or Khipu Keeper, is funded by the National Science Foundation, the Dumbarton Oaks Foundation, Harvard University, and the John D. and Catherine T. MacArthur Foundation. Although the 16th century Spanish conquistadors did their best to destroy as many khipu as possible, some 600 Inca khipu are in existence today; Urton and Brezine have been able to input data on approximately 300 to date.
Among the most productive collections yet discovered are from an Incan village site called Puruchuco. Puruchuco was excavated in 1956, and stored beneath the floor of one of the rooms in the palace at Puruchuco was found a cache of 21 khipu. If Garcilaso was correct, and khipu were accounting records for each village, these khipu represent the accounts for some sort of administrative information for Puruchuco. These twenty-one khipu were added to the database. Urton and Brezine began querying the database looking for similarities across and among the khipu, and quickly began to find them. Eventually, they noticed a systematic pattern in the khipu, and khipu illustrating three levels of administrative complexity were discovered among the collection from Puruchuco.