Quipu: The Inca Records Tied in Knots
The Inca ruled a huge mountain empire in South America during the 1400s and early 1500s, yet they had no written alphabet that scholars have found. Instead, their officials kept records with quipus, which were bundles of colored cords tied with knots. A quipu had one long main cord, and many thinner cords hung down from it like a fringe.
The knots were the key to the system. Their type, their position along a cord, and the color of the cord could all carry meaning. Experts believe that many quipus recorded numbers, because the knots were arranged to show ones, tens, and hundreds in a decimal system much like the one we use today. A cord with a few knots near the bottom and more knots higher up could stand for a precise count of llamas, bags of corn, or workers.
Specially trained record keepers made and read these cords. They traveled along the empire's mountain roads and reported on the goods stored in warehouses and on how many people lived in each district. Because a quipu was light, a runner could carry one across a high pass much faster than he could carry a heavy load of anything else.
Some scholars think a few quipus may also have held names or stories, not only numbers, but nobody has fully decoded them. Most were made of cotton or the wool of llamas and alpacas, and only a fraction survive in museums today. How to read the rest remains a puzzle that researchers are still working to solve.