Warazan - Japanese numerical records made of straw, 1930

For many years and well into the 20th century the people of Japan’s Ryukyu Islands recorded numerical data by means of knots on strands of rice straw. The method used the number system to the base 10 and allowed the storage of numbers without knowing how to write them.

A similar method was used in the Inca civilization. Knotted strings (known as quipu) were used to record administrative data of religious, chronological and statistical relevance. The method also permitted the recording of individual steps and intermediate results of calculations.

We thank the japanologist Professor Josef Kreiner of the University of Bonn for his help with the acquisition of these very rare exhibits.