Origami, the Japanese art of folding paper, is probably familiar to most people through the image of the paper crane. A simple sheet of coloured paper is folded, without cutting or gluing, into the graceful shape of a bird. The word itself comes from the Japanese oru, meaning to fold, and kami, meaning paper. For centuries origami was regarded mainly as a children's pastime and a ceremonial decoration, but in recent decades it has also become a subject of serious scientific study.
The art began shortly after paper itself arrived in Japan from China in the 6th century. Because early paper was expensive, folded paper figures were used only for formal purposes, such as wrapping gifts at court or decorating religious shrines. As paper became cheaper, folding spread to ordinary households, and many of the traditional models, including the crane, were developed.
In the second half of the 20th century, a small group of enthusiasts, led by the Japanese artist Akira Yoshizawa, began treating origami as a serious art. Yoshizawa invented a standard system of diagrams, now used worldwide, which made it possible to share new designs with others. Modern folders now create astonishingly complex models, from insects with individual legs and antennae to life-sized human figures.
Researchers have also begun to see folding as a powerful idea in engineering. Satellite panels that must open in space, medical stents that expand inside blood vessels and airbags that inflate inside cars all borrow principles worked out by origami artists. What began as a way of playing with paper has turned out to have surprising practical value.