Quipu and Inca Record Keeping
In the fifteenth and early sixteenth centuries, the Inca state governed a large part of the central Andes from Cusco, in present-day Peru. Its officials used khipus (also called quipus), textile records made from knotted cords, to track quantities moving among communities, storehouses and provincial centers. Khipus drew on older Andean cord-keeping traditions, but under Inca rule they became practical tools for recording tribute, supplies, labor and population. Their structure could preserve a count; trained readers connected that count to the thing being counted and to the transaction behind it.
Cords and decimal numbers
A khipu began with a long primary cord. Smaller pendant cords hung from it, and subsidiary cords could branch from pendants; some examples also have cords attached above the primary cord. Cotton or camelid fiber from llamas and alpacas was twisted into cords, then arranged by length, color, attachment and direction as well as by knots. The numerical recording usually sits on pendant, subsidiary or top cords; primary cords can also carry knots. Their arrangement gave a reader more than a row of isolated totals: cords could be grouped and nested, with subsidiaries adding finer categories beneath a broader one.
In a common Inca numerical format, each pendant cord used a base-ten place-value pattern. The units position lay farthest from the primary cord, with tens, hundreds and higher places progressively nearer it. A figure-eight knot marked one at the units position; long knots with two to nine turns marked unit values from 2 to 9. At tens and higher places, counted single knots gave the digit. An empty place represented zero. A cord for 204 therefore had two single knots in the hundreds position, no knot in the tens position, and a four-turn long knot for the units. Some knots were also tied in different directions, and colors or cord patterns could help distinguish categories, though their meaning depended on the record’s context.
The cords could represent a hierarchy of quantities as well as individual numbers. A pendant might carry a total, while its attached subsidiaries broke that amount into more specific groups. In some khipus a cord above the primary cord summed several pendant values. This made a record useful for comparing a category with its subdivisions or checking whether component amounts corresponded to a larger account. The knot pattern provides the number; the reader’s knowledge of cord order and the account provides its category.
Accountants and the route of a record
The textile accounting system also extended beyond imperial stores: historian Terence N. D’Altroy says khipus also tracked community herds, a practice he notes continued into modern times. Spanish chronicler Pedro de Cieza de León, writing in the mid-sixteenth century, describes quipucamayos (khipu specialists) working with provincial rulers. His account names tribute in silver, gold, cloth, flocks and even firewood; some provinces also owed laborers for public building projects. Cieza says trusted assessors visited settlements to note population and productive resources before reports went to Cusco and tribute was assigned. Specialists recorded what a district owed, then reported the account to inspectors at intervals. In practice, a count was attached to an obligation: who had supplied which goods, how much had arrived, and what remained due.
Cieza also describes how accounts moved through the administration. Tribute from surrounding settlements was brought to larger provincial centers. A local record keeper entered incoming goods and recorded stores issued to soldiers or sent toward Cusco. Inspectors from Cusco compared the accounts and expected the totals to balance. In another passage, Cieza says that yearly counts of births and deaths were recorded by province and carried to Cusco. He connects those figures to decisions about tribute assessments, military service and the needs of widows or poor households. The described record chain connected community contributions to provincial storage, military issues and transfers to Cusco.
Archaeology offers a close view of this work at Inkawasi, an Inca garrison and storehouse in the Cañete Valley on Peru’s south coast. Excavations recovered 34 khipus in the storage complex. Some were found with chili peppers, peanuts or black beans. Archaeologists Gary Urton and Alejandro Chu propose that these may be the products represented in the records. They also found paired khipus with very similar quantities, which Urton and Chu interpret as evidence of checks between accounts. The archaeologists suggest that grids impressed into two sorting-room floors may have helped workers measure and count produce consistently. At this storehouse, khipus were part of provisioning: accounting worked alongside the storage of food for troops.
Numbers, memory and later readings
Early colonial writers describe both numerical accounts and memories of Inca history. Cieza says elders selected for memory learned songs about rulers and events in the provinces; in the same account, he says khipus recorded expenditures and provincial contributions. Cieza also recounts a demonstration at Marcavillca in Xauxa, the central Peruvian region around modern Jauja. The local lord Guacarapora brought out khipus that, he said, listed what he had delivered to the Spaniards since Francisco Pizarro, the Spanish conquistador, arrived. Cieza saw accounts for gold, silver, clothing, maize, sheep and other goods, and Guacarapora explained them. Because those entries recorded goods given to Spaniards after Pizarro arrived, the demonstration shows the inherited technique used for a colonial transaction.
Some surviving khipus contain regular decimal sequences that researchers can read numerically. The number on a surviving khipu may be readable even when its category depends on an accompanying oral account or other context. A 2019 Harvard dissertation by Jon Clindaniel proposes a preliminary grammar for nonnumerical signs alongside these numerical readings.
For the wider cultural setting, see Inca Culture and Arts.