One more reccurrence of this topic in the users list:
http://www.nabble.com/Blue-for-success-to18742354.html#a18742354
In particular, see http://groups.yahoo.com/group/ParthenonWeekly/message/232
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Q. "Why do Japanese people say that they have blue traffic lights
when they are really green?"--Question submitted by John Sypal
A. According to the book, Japan From A to Z: Mysteries of Everyday
Life Explained by James and Michiko Vardaman, the first traffic
signals in Japan were blue instead of green, but the blue lights were
difficult to see from a long distance away so they were replaced with
green ones. Vardaman says that the custom of referring to traffic
lights is a holdover from those days.
This sounds like a good explanation, but the problem with it is that
you will hear Japanese people refer to other green things (like
cucumbers, spinach, and sometimes grass) as being blue as well. This
is because historically, Japanese people considered green to be a
shade of blue. For example, the Chinese character for blue,
pronounced ao is made up of two characters, iki (life) and i (well)
and refers to the colour of plants which grow around a well, a colour
between green and blue. When Chinese people see the character, they
say it means green, but Japanese people say it means blue. Japanese
books on colours tell us that there are four tertiary colours: red,
blue, white and black, and that all others are shades of those four
main ones. Ao, therefore, is a sort of ideal blue, halfway between
green and blue. The sky is said to be blue, but it is a different
shade of ao than a traffic light is. Tree leaves are said to be
green, but green is a shade of ao, like crimson is a shade of red.To
read an interesting debate on the nature of "blueness", visit
http://server5.ezboard.com/fhumanjapanesejapanesegrammar.showMessage?
topicID=20.topic. In another interesting cultural difference relating
to colour, Japanese children always colour the sun red instead of
yellow.