Sangaku, Japanese Temple Geometry, is the exquisite tradition carried out for centuries in Japan of hanging wooden tablets containing mathematical problems in Buddhist and Shinto Shrines.  In May, 2008, my book Sacred Mathematics, with Hidetoshi Fukagawa, the world's leading expert on sangaku, will be forthcoming from Princeton University Press. Below are a few photographs of sangaku taken by Hidetoshi.

This is the Kaizu Tenma Shrine in the Shiga prefecture. A sangaku of length 520 cm by 26 centimeters is visible under the right eave. The sangaku contains thirty problems. High resolution image (1 Mb)
This tablet, 450 centimeters long and 150 wide, was hung at the Haguro shrine in the Yamagata prefecture in 1823 and contains eleven problems. It is considered the most beautiful tablet in Japan High resolution image (4.8 Mb)
This tablet, which was hung at the Souzume shring in the Okayama prefecture, is not actually a sangaku but a votive tablet that shows a group of people enjoying mathematics. The teacher is in the center surrounded by a group of men and women who are discussing mathematics and solving high-degree equations. High resolution image (2.5 Mb)
This beautiful tablet, which contains twelve problems, was hung in 1865 at he Kinshouzan shrine in the Gifu Prefecture. The third problem from the right was presented by a sixteen-year-old girl. High resolution image (608 K)
This tablet dates from 1814 but was discovered only in 1994 at a temple that was about to be destroyed. High resolution image (700 K)
This triple tablet was hung in 1797 in the Onnma shrine in the Aichi prefecture and contains 30 problems. It measures 520 centimeters by 26. High resolution image (1016 K)