What Are Quipu, the Knotted Cords the Inca Used to Record History?

Quipu (also spelled “khipu”) were knotted cord devices used by the Inca Empire to encode information — primarily numbers, and possibly language — using a sophisticated base-ten positional system that researchers are still working to fully decode.

What Exactly Is a Quipu?

A quipu consists of a primary horizontal cord from which dozens — or even hundreds — of pendant strings hang down. Each string could itself branch into subsidiary cords, creating a layered, tree-like structure. The knots tied along these cords were not random: the Inca used three distinct knot types — figure-eight knots, long knots, and single knots — placed at precise positions to represent numerical values within a base-ten system. The position of a knot on its cord determined its place value, much like the digits in a written number.

Some quipu contained up to 1,500 individual cords, making the most complex examples among the most intricate recording devices ever produced in the pre-Columbian Americas. Color, cord material, twist direction, and attachment style are also believed to carry meaning — layers of encoded information that researchers are only beginning to untangle.

Who Made and Read the Quipu?

Specialist record-keepers known as quipucamayocs — literally “knot-keepers” — were trained for years to create and interpret these devices. They served an administrative function across the vast Inca Empire, which at its height stretched along the western coast of South America from modern-day Colombia to Chile. The quipu system allowed the empire to track census data, tribute payments, military records, calendrical information, and agricultural inventories across thousands of miles of difficult terrain — all without a conventional writing system.

How Old Is the Quipu Tradition?

The quipu tradition is far older than the Inca Empire itself. The earliest known quipu-like object was discovered at Caral, an ancient site in present-day Peru dating to roughly 2600 BCE — placing it contemporaneously with, or even earlier than, the construction of the Great Pyramid of Giza. This suggests that knotted cord recording was not an Inca invention but rather a tradition inherited and refined over thousands of years of Andean civilization.

Why Can’t We Fully Read Them?

Two major obstacles stand in the way of a complete decipherment. The first is destruction: in 1583, the Third Council of Lima issued an order for the systematic burning of quipu, classifying them as instruments of idolatry under Spanish colonial rule. An incalculable volume of recorded Andean knowledge was wiped out in the decades that followed. Fewer than 1,000 quipu survive today, scattered across museums and collections worldwide.

The second obstacle is interpretive. While the numerical function of quipu is well established, a growing body of research — most notably work by Harvard anthropologist Gary Urton — suggests that some quipu may have encoded narrative or phonetic language, not just numbers. Urton proposed a binary coding system capable of representing thousands of distinct signs, hinting that quipu could constitute a full writing system. But without a bilingual “Rosetta Stone” equivalent for quipu, confirming this hypothesis remains one of archaeology’s most tantalizing open problems.

What Are Researchers Doing Today?

Modern efforts to decode quipu combine traditional anthropological fieldwork with cutting-edge computational analysis. Researchers are digitizing surviving quipu, cataloguing their physical properties, and applying machine learning techniques to search for patterns that might reveal linguistic content. Some scholars are also working with communities in the Andes where living quipu traditions — though simpler in form — still survive, hoping that indigenous knowledge might illuminate what the historical record cannot.

The quipu stands as a powerful reminder that human ingenuity finds many paths to preserving memory. An entire empire spoke through knots. We are still learning to listen.