Matching Khipu are pairs or triplets of samples bearing identical or near identical numerical sequences and, in some cases, color patterning.
Such matches may have been made and used as a part of the system of checks and balances that was an important feature of accounting practices in the Inka state.(See Garcilaso's description of khipu practices). A few matches are "exact": cord for cord, the values on one khipu equal the values on another. More often, matches are "close": some cord values are identical, and others are close, but not exact, or in some cases in a slightly different order. Some khipu have internal matches: sequences of numbers that repeat within the khipu itself, often clearly separated by spacing or color changes.We do not yet know precisely how matching khipu were created or used. There are several possibilities:
--Duplicate records could have been made as a part of a system of checks and balances.
--Duplicates might have been made for distribution: one copy for the town, one copy for the capital Cusco.
--In some close matches, all values on one khipu are higher than the values on the second khipu. This could indicate a change through time: an increase or decrease in what was being recorded.
--There are a couple of instances of three matching khipu. There is some evidence that the data from small khipu may have been assimilated into a larger one. (See the Calendar Khipu.)
The Khipu Database has been invaluable in identifying khipu matches. Several of the known matches can be viewed by following the links to the right.