From the Independent: Inca may have used knot computer code to bind empire. [Update: sorry, article no longer available.]
They ran the biggest empire of their age, with a vast network of roads, granaries, warehouses and a complex system of government. Yet the Inca, founded in about AD1200 by Manco Capac, were unique for such a significant civilisation: they had no written language. This has been the conventional view of the Inca, whose dominions at their height covered almost all of the Andean region, from Colombia to Chile, until they were defeated in the Spanish conquest of 1532.
But a leading scholar of South American antiquity believes the Inca did have a form of non-verbal communication written in an encoded language similar to the binary code of today's computers. Gary Urton, professor of anthropology at Harvard University, has re-analysed the complicated knotted strings of the Inca - decorative objects called khipu - and found they contain a seven-bit binary code capable of conveying more than 1,500 separate units of information.
In the search for definitive proof of his discovery, which will be detailed in a book, Professor Urton believes he is close to finding the "Rosetta stone" of South America, a khipu story that was translated into Spanish more than 400 years ago.
"We need something like a Rosetta khipu and I'm optimistic that we will find one," said Professor Urton, referring to the basalt slab found at Rosetta, near Alexandria in Egypt, which allowed scholars to decipher a text written in Egyptian hieroglyphics from its demotic and Greek translations.
It has long been acknowledged that the khipu of the Inca were more than just decorative. In the 1920s, historians demonstrated that the knots on the strings of some khipu were arranged in such a way that they were a store of calculations, a textile version of an abacus.
Khipu can be immensely elaborate, composed of a main or primary cord to which are attached several pendant strings. Each pendant can have secondary or subsidiary strings which may in turn carry further subsidiary or tertiary strings, arranged like the branches of a tree. Khipu can be made of cotton or wool, cross-weaved or spun into strings. Different knots tied at various points along the strings give the khipu their distinctive appearance. [continue]
If this sounds interesting, take a look at the What is a khipu? page for an explanation of how khipus (also spelled quipus) record information.
Related link:
String theorist: Anthropologist Gary Urton untangles the mystery of Inkan khipus - from the Harvard Gazette
Related books:
Mathematics of the Incas: Code of the Quipu
Signs of the Inka Khipu: Binary Coding in the Andean Knotted-String Records
Narrative Threads: Accounting and Recounting in Andean Khipu
Update:
String, and Knot, Theory of Inca Writing - New York Times, August 12th, 2003. (NYT requires free registration.)