Components

Point of interest: 勾股弦(こうこげん)and other math terms

POI
勾股弦(こうこげん)and other math terms
107 words
For more on this topic, see the 勾 essay in the Joy o' Kanji essay collection.
The archaic term
こうこげん
勾股弦
comes from a type of math that the Chinese invented and that the Japanese further developed in the Edo era (1603–1867), calling it
さんぽう
算法
. In the Meiji era (1868–1912), the Japanese coined the name
わさん
和算
to draw a contrast to
ようさん
洋算
(Western math).
In China, a book from the Han Dynasty (206 BCE–8 CE) mentions the Pythagorean theorem. It's hard to know whether the Chinese learned it from the Greeks or whether the Chinese themselves discovered the theorem.
One period novel published in 2006 features an Edo-era girl, a math whiz known as
さんぽうしょうじょ
算法少女
. In one scene, she uses the theorem called
こうこげん
勾股弦
ていり
定理
!

Kanji used in this point of interest

コウ    capture   
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コ   thigh   また crotch; tines (of a fork)   
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ゲン   つる bowstring, cord   
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サン    calculate   
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ホウ   ハッ   ホッ    method   
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ワ   オ    peace, harmony   なご to be calmed down   なごやか calm, gentle   やわらぐ to be softened   やわらげる to soften; to alleviate   
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ヨウ    ocean   
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ショウ   すこ a little   すくない few   
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ジョ   ニョ   ニョウ   woman; female   おんな woman   め woman   
テイ   ジョウ   determined   さだ decidedly, truly   さだめる to decide, determine   さだまる to be determined   
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リ    logic   
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