The Incan empire flourished in Peru and parts of Ecuador, Bolivia, Chile and Argentina from about 1400 CE to 1560 CE. They had neither a written language nor a written number system. However, maintenance of the bureaucracy of their empire still required accurate record keeping. They developed a system of cords and knots to represent numbers called a quipu.
A quipu consisted of a main cord with pendant cords hanging from it and sometimes a top cord extending above it. Hanging from a pendant or top cord might be subsidiary cords. Subsidiary cords might themselves have further subsidiary cords and so on. Colors and grouping of cords were used to group information in a quipu.
Quipus used three different types of knots. The position and number of these knots on a cord indicated a base ten number. The units position was always on the bottom.
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The single knot. Used in multiples to represents digits in the tens and higher places. |
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The long knot (with four turns.) Used to represent digits in the units position. The number of long turns determined the digit. |
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The figure eight knot. Used to represent one in the units position. |
