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Chapter 6
Plate 6.2. The original illustration for problem 2, originally proposed by Sugita Naotaki, as it appears in Shino Chigyo¯’s 1837 book Kakki Sanpo¯. On the same page can be seen a drawing for a more advanced problem, similar to problems 16 and 17. (Aichi University of Education Library.)
Example: If α = 35, β = 28, and γ = 21, then S = 144. We give both a traditional and a modern solution on page 210.
Problem 3 This problem was originally hung in 1806 in the Atsuta shrine by Ehara Masanori, a disciple of Kusaka Makoto (1764–1839). The tablet, which contained only this problem and no solution, was subsequently lost. However, at an unknown date the mathematician Kitagawa Mo¯ ko (1763–1833) visited the shrine and recorded the sangaku in his note “Kyuka Sankei,” or “Nine Flowers Mathematics,” along with his solution. More recently, the shrine constructed a replica from Kitagawa’s manuscripts (see plate 6.3). Warning: This may be the most involved exploitation of the Pythagorean theorem you have ever seen.