Unraveling an Inca mystery: in the Andes, a burial-site discovery of knotted string called khipu has experts wondering what the ancients were trying to tell us.

• Author: Hardman, Chris

AT LAGUNA DE LOS CONDORES near Chachapoyas in Peru, laborers are cutting down trees to gather lumber for a hacienda under construction. As they watch a tree fall, one of the men glances across the lake and spies a painting on a cliff face. Motivated by the possibility of discovering gold, the group treks around the lake until they find a site adorned with primitive rock paintings that lead the way to seven, aboveground burial chambers. They have discovered a burial site for the Chachapoyas, an isolated civilization that. ruled these northeastern lands from A.D. 700 until the Incas conquered them in the fifteenth century. The burial chambers yield ancient artifacts, ceramics, textiles, and more than two hundred mummies.

But these men aren't interested in the historical significance of their find. With gold in mind. they hack into the mummies and loot the site for several months until the police shut down their operation. Eventually, the valuable artifacts are recovered and the site is handed over to Peruvian archaeologist Sonia Guillen and her colleague, Adriana von Hagen. While much of the scientific world marvels at the discovery of a couple hundred mummies in funerary garb, a smaller group of scholars turn their attention to what else is in the burial chambers--thirty-two well-preserved knotted strings called khipu. Is this the clue the scientists have been seeking? Were the ancient inhabitants of Peru finally speaking to them from the past?

The mystery in the Andes is this: How did the Inca--the largest empire in the Americas until the Spanish came in 1532--rule and administer an area covering thousands of miles with no form of written word? At the peak of their power in the early sixteenth century, the Inca state stretched along the Andes from present-day southern Colombia through Ecuador, Peru, and Chile, over to Argentina, and into the Amazon basin. The rulers in Cuzco kept detailed records of births, marriages, tributes, religious rituals, and other activities throughout their empire using knotted and dyed strings. For the last five hundred years, historians and scientists have been trying to solve the mystery of the khipu and decode the information within. And this most recent discovery of just a decade ago at Laguna de los Condores has provided valuable clues to its unraveling.

The word khipu is from Quechua, the language of the Inca, and means knot. A khipu is made of cotton or sometimes camelid fiber and varies in color from white to brown or green. When wrapped for storage, khipu resemble a string mop, but when spread out, they reveal a complex array of knots and strings. Most have one main cord on a horizontal plane with pendant cords hanging from it. The pendant cords may have their own attachments called subsidiaries. Some khipu have as many as ten or twelve levels of subsidiaries. Knots are strategically tied on the pendant cords and subsidiaries to represent numerical values. Most of the seven hundred khipu in existence today are from the time of the Inca--the early 1400s to the early 1500s--but it's hard to know exactly where they came from because most were dug up by looters and sold to museums and private collections.

Much of what we know about the khipu and the type of information it stores comes from the Spanish chroniclers. Through drawings and text they described how the khipu...