Mathematical Treasures of Japan in the Edo Period: Practical Mathematics

Frank J. Swetz (Pennsylvania State University)

Sanpo dojimon (Questions Children Ask About Mathematics, 1784) was a collection of problems concerning topics such as weights and measures, simple surveying, and the use of mathematical instruments. It is considered a Japanese classic of pedagogy of mathematics. The work's author was Murai Chuzen. A frontispiece depicts children asking their elders a question concerning mathematics, perhaps the distance to the sun, a question with which Chinese mathematicians grappled a millennium previous.

A scene of kite flying warrants the question, “How high is the kite?”

A variety of geometric situations involving inscribed configurations allows for a family of questions.

The illustration below demonstrates a simple technique for determining distance. Can you figure it out?

Two commoners have brought their feudal lord three baskets full of some commodity. Perhaps they are paying their required tribute (taxes) and there is a question concerning the capacities or weights of their contribution.

An illustration of a Japanese theodolite of this period accompanied by instruction as to its use:

The illustration shows the employ of a theodolite in taking a downward sighting.

These images are presented through the kind cooperation of the National Diet Library, Japan, and are used with permission. They were obtained from the library’s digital gallery exhibit, Japanese Mathematics in the Edo Period, where a complete examination and viewing of the item presented above can be found.

Index to Mathematical Treasures