# Picture of the week: a Sangaku

This five-meters long triple tablet was hung in 1797 in the Onnma shrine in the Aichi prefecture (Japan) and contains 30 problems. It is called a Sangaku, a mathematical ex-voto representing solved geometrical problems. A book about Sangakus is forthcoming, Sacred Mathematics: Japanese Temple Geometry.

What do our friends interested in the anthropology of maths (Christophe, Helen, Hugo…) think of this interplay of religion and geometry? As for me, growing up in catholic Brittany, I have seen my share of weird ex-votos (the last one on my list was this toy boat, last June), but this tops everything else…

(found on Science News).

### 3 Comments

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## Hugo Mercier 10 November 2008 (00:00)

It’s funny to contrast the sense of deep intermingling of religion and science (well, mathematics and therefore reason at least) that comes from these ex-votos with the situation in Christian Europe at the same period.

## Olivier Morin 10 November 2008 (00:00)

Well, I’m not entirely sure the contrast is that striking. When Descartes discovered cartesian coordinates, his very first move was to pledge himself to go on a pilgrimage to Notre Dame de Lorette in thanks (which he did). It is not quite unimaginable to figure Descartes offering equations as ex-voto to Mary.

## Charles Stafford 10 November 2008 (00:00)

Although the anthropological study of ”number”, numeracy and numerical cultures has been fairly limited – the contrast with the anthropology of literacy is striking! – there seems to be a renewed interest in taking up these themes. For example, Jane Guyer and colleagues recently organised a large workshop on ”number as inventive frontier” at Johns Hopkins University (see herel). I’ve also published several papers recently on Chinese religion/cosmology which (like the Japanese case cited in this post) is heavily numerological in orientation. But of course there are many other recent examples …