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written in English

Traffic lights Why does the Japanese call “Blue light”

Hi! Have you been Japan? In Japan, the Japanese says blue light to see green light. Traffic lights is 3 colors. Red Yellow and Green. Why??
I checked the reason.


The color of the signal is decided in an international standard

It decide to use five colors of red, green, yellow, white, the blue in CIE (the International Commission on Illumination) which is an international standardization group prescribing light, illumination, a color, color space, and a range or the intensity of light of the chromaticity are decided each. The color used for a traffic light is three colors of the red, green, yellow of these. (white and the blue are used for aviation signals)
There seems to be the reason that it is easy to distinguish relatively well while view including rain and the fog is bad
In Japan, red,yellow and green are used.

Why does the Japanese call “Blue light”

【Changes from green to a blue green color】
For old days, Japanese used "a green signal" But, for a person with partial color blindness, it was hard to be able to tell the difference between "a red light" and "the green signal", and therefore it was changed in "the blue green color" that it was easy to distinguish by a person of partial color blindness. The Japanese Metropolitan Police Department seems to establish an available color in the green standard range that CIE determines. Japan changed the legal notation from green light to the blue light .
But color is Green light!!


【Why is green called blue?】
 Origen is long long ago. There was not expression of "the green", and both modern "green and blue" seemed to be included in "blue" in Japan until (the - Kamakura era terminal in the Heian era) in about 1100 in the Christian era. In the present age when "the green" can be distinguished from "blue", Japanese may call blue vegetables, bluish-skinned fish, the green thing including green leaves with blue. For example,Japanese call “Ao ringo(Blue apple)”green apple. Therefore Japanese was accepted without sense of incongruity even if I came to express a green signal with a green light.
In other words the Japanese history is related.

At last

Japanese sense of color is not abnormal.
But I am a 43-year-old Japanese woman, I though "why is blue? My son is 5 years old,he always me"Why Blue?that's color is greeen!!It`s green "!! I guess there are a lot of people who have the same question from the Japanese Internet. The day called "the green signal" may come in the future in Japan.


-written in English