Traditional Japanese Geometry - John Rigby
23rd February 2002
During the Edo period (l603-1867), when Japan was almost completely cut off from the western world, a distinctive style of mathematics, called wasan, was developed. Results and theorems were originally displayed in the form of problems, sometimes with answers but with no solutions, inscribed on wooden boards and accompanied by beautiful coloured figures. These boards, known as sangaku, were hung under the eaves in shrines and temples. Later, books appeared, either handwritten or printed from hand-carved wooden blocks, containing collections of sangaku problems with solutions. The problems available examine the golden ratio, circles & tangent lines, triangles, squares and rectangles.