A Khipu was a knotted string object used by the Incas as a device for for record keeping and accounting.
More recent studies indicate that it may be more likely a 3 dimensional form of writing.
During the period of approx 1400 – 1532 AD the Inca Indians of South America had an empire that stretched from Ecuador through central Chile, with its heart in Cuzco, a city in the high Andes of
southern Peru. They had no written language. Yet they left behind fascinating evidence of other civilized attributes: monumental architecture, technology, urbanisation and political and social
structures to mobilize people and resources. How they achieved this is one of the mysteries of modern civilization.
The answer almost certainly lies in the khipu. These intriguing string objects were found wrapped around Inca mummies. Made of cotton or llama hair, most of the 400 to 550 year old khipu are
extremely fragile and many have crumbled into dust at the first touch of modern hands. In the conventional view of scholars, most khipu (or quipu, in the Hispanic spelling) were arranged as knotted
strings hanging from horizontal cords in such a way as to represent numbers for bookkeeping and census purposes. There are studies that now consider that the khipu may have even been a type of coded
written language. These knotted string artifacts were the medium for expression by the very real splendor of the Andean civilization.
Harvard University has a Khipu Database Project involved in measuring, recording and comparing the approx 600 khipu still in existence in various locations, in an attempt to understand what they
mean and how they were used. http://khipukamayuq.fas.harvard.edu/
In his book, Signs of the Inka Khipu, recently published by the University of Texas Press, Dr Urton said he had for the first time identified the constituent khipu elements. The knots appeared to
be arranged in coded sequences analogous, he said, to "the process of writing binary number (1/0) coded programs for computers." http://www.ee.ryerson.ca/~elf/abacus/inca-khipu.html
The Inca's had developed a form of recording that forces reconsideration of writing as we generally understand that term. As a numeric-logical system, khipus are related to that part of human
intellectual endeavour generally regarded as mathematics. The khipus did not influence any practitioners of Western mathematics, due to remoteness. Europeans commercial arithmatic and bookeeping was
influenced by Arabian and Italian systems, and we will never fully understand the direction or form of the khipu, or where the ideas of their creators may have led.
Unfortunately the intellectual endeavour of khipu making came to an abrupt halt in the 16th century, with the arrival of the Spanish conquistadors in South America, virtually wiping out the Inca
people in one generation of 30 years. The Spanish burned every khipu they found as they believed they were ungodly. ("Mathematics of the Incas: Code of the Quipu", Maria Ascher & Robert