Quipu: tie a knot in it

by Jo Brodie, Queen Mary University of London

Quipu (the Quechua word for ‘knot’) are knotted, and sometimes differently coloured, strings, made from the hair fibres of llamas or alpacas. They were used by people, such as the Incas, living hundreds of years ago in Andean South America. They used the quipu to keep numeric trade or military records. A ‘database’ was formed of several of the strings tied together at one end. Each string stored numbers as different kinds of knots at different positions along the strings, with positions for ones, tens, hundreds, etc. It worked a bit like an abacus, but with much less danger of losing your work if you turn it upside down. The number ‘1’ was represented as a figure-of-eight knot in the ones position and ‘40’ could be indicated by four simple knots in the tens position. Not many quipu survive and even fewer have been decoded, but anthropologists have begun to find evidence that they might contain not just numbers but a written (well, a tactile) form too.

---

Make your own Quipu

Make your own Quipu decoration or necklace that represents something by tying knots in coloured string or ribbons.

1. It could keep track of important numbers for you, such as how much pocket money you have at the end of each week, making a new string (or ribbon) for each week, or
2. Store some sequence of numbers in a sequence of quipu like the 3 times table or the square numbers or the Fibonacci numbers…, or
3. Invent a code such as A=1, B=2, … and store a message on your Quipu by spelling it out in numbers and so knots.

To make your Quipu more colourful tie different coloured strings together end to end to make a single Quipu. One colour string then represents ones and the next tied to it represents tens for a single number and so letter (and so on). Use different colours for your next Quipu.

---

More on …

• Back (page) to the drawing board
• Cunning Computational Contraptions

Related Magazines …

• Issue 28 – Cunning Computational Contraptions

---

This article was funded by UKRI, through Professor Ursula Martin’s grant EP/K040251/2 and grant EP/W033615/1.