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ao seems to be used very much interchangeably for both blue and green. Why is that so, and how does 緑 midori play into this?

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I'm sure I heard somebody saying gairaigo "blue" in the last 2 or 3 days also... – hippietrail Jun 13 '11 at 12:42
@hippietrail: ブルー is definitely used in modern Japanese, but I usually hear it in reference to the emotion rather than the color. – Derek Schaab Jun 13 '11 at 12:55
@Derek: Ah that could be, it was among volunteers cleaning up Kesennuma/Minami Sanriku and I could by know means follow the rest of what was being said. – hippietrail Jun 13 '11 at 13:00
@hippietrail Otsukaresama! _(_ _)_ – deceze Jun 13 '11 at 13:05
The distinction of blue from yellow-green is one of the last "basic" color terms (one word) to evolve in most languages, according to the seminal studies of Kay and Berlin: See this Wikipedia text and chart for info. You can even see it in English: Apparently, once upon a time in Old English, we did not distinguish between yellow (yellow-greenish) and blue; if you check the etymologies, one finds that they go back to the same PIE root, *bhle-was. – Uticensis Jun 13 '11 at 17:50
up vote 37 down vote accepted

Beside some of the historical examples mentioned by Derek, there is also an inherent nuance that separates 青 from 'blue', as it is commonly understood in Western culture (and similarly, albeit less strongly, for 緑 and 'green'). This is not unique to Japanese-English and probably applicable to any pairs of sufficiently separate cultures: colours are, for a large part, an artificial construct and there is only limited reasons two people should pick the same arbitrary frontier along the green-blue continuum (or red-orange, or yellow-green etc). I recommend digging in Google Scholar for more on that, but it's worth mentioning that there is much debate on what the causes and extent of these differences between cultures are.

Anyway, back to 青/緑: leaving aside the fact that the past 100 years of intermingling with Western culture have no doubt influenced the native Japanese perception of these colours, there is still a real difference between the range of what a Japanese will call 青い and a Westerner call 'blue' (talking about pure colours here, not objects' traditional colours, which might be tied to historical reasons). 'Blue' for 青 and 'green' for 緑 are just approximations (as are probably most other native colour translations).

A diagram might be the easiest way to put it. Assuming that horizontal line represents the true continuum of hues from blue to green, and the vertical bars, the separation between the two colours in Japanese and English respectively, you'd have:

    青い        |  緑
  Blue  |  Green

As a result, when talking about something on the far left (say, the sky) or the far right (say, fresh verdure), both English and Japanese words agree quite well. If you pick things that are in that middle area where the definitions do not match, you get these quizzical looks and people arguing "what do you mean green? it's obviously blue!" etc.

Sorry for the longwinded answer to what is a fairly basic/obvious point... ;-)

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Don't apologize this is a great answer! – hippietrail Jun 13 '11 at 23:58
For more (completely Japanese-unrelated) musings on the subjectivity of colour perception and naming, I strongly recommend checking this awesome xkcd project that surveyed internet users on how they view colours and analysed their results (unfortunately without nationality information)... particularly the colour naming map, which is a 2D version of what I tried to do above... – Dave Jun 14 '11 at 2:45
excellent explanation! – Pablo Jul 18 at 14:16

This page in the 日本語Q&A over at ALC addresses this question. Apparently the historical definition of 青【あお】, even when defined narrowly, covered an entire range of colors which are today separated as 青【あお】, 緑【みどり】, and 藍【あい】 (indigo). This trend carried into the modern language, and many words which refer to things that are actually 緑【みどり】 still use 青【あお】: 青葉【あおば】 and 青竹【あおだけ】 are two examples given on the linked page. (This in spite of the fact that 緑【みどり】 has existed alongside 青【あお】 all this time.)

Apparently when traffic signals came along, 緑信号【みどりしんごう】 was the official name at first, but it was eventually overtaken by 青信号【あおしんごう】 in common use and this latter name became the official term.

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This actually happens in all languages, it's one of the puzzles of linguistics. They're still trying to figure out how and why Latin colour words were applied. – hippietrail Jun 13 '11 at 12:57
More on color (non-)universality. – Kosmonaut Jun 13 '11 at 19:17

This partially also has to do with the fact that in old Japanese they only used four colours: あか・あお・しろ・くろ. Obviously, with this limitation, あお came to represent a wide range of different cool shades. Then once more "colours started to be used", a lot of things retained their original descriptions as あお.

Edit: Here is that handout I have from my Japanese teacher which I describe below in the comment. It is from a book she has, but I don't have the reference for it.


* 昔の日本では、あか(紅)・あお(緑)・しろ(白)・くろ(黒)の四色
  文献上で「緑」が用いられるのは、平安時代ごろからです。 *注)平安時代:794〜1185
* 1930年に日本で初めて信号機が設置されたとき、
* あお   青・蒼・藍 ー> 空・顔色・信号・草
  みどり  緑・翠・碧
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@istrasci: Do you have any sources for this claim? I must admit this sounds a little sketchy... Even if you discount the numerous "○色" compounds (茶色 etc.), which I see no reason to, I am pretty sure you would still have more than 4 colour-defining words in older Japanese. 紫【むらさき】 to pick one at random, is pretty old. The Jp Wikipedia for dyes lists many more, in use since "ancient times"... – Dave Jun 14 '11 at 14:45
Yes, admittedly it sounds very questionable. The only source I have is a type-up I received from my Japanese teacher. I know she didn't make it up, but I don't know where she got it from. I'll add it later (during my lunch hour) as a comment. – istrasci Jun 14 '11 at 15:27
Would love to hear more, thanks... At the risk of stirring up some old controversies, I'd recommend taking any statement that starts by "Japan always had/has X of Y, unlike all other cultures" with a huge grain of grain of salt, regardless of what native authority figure utters it. In my personal experience the love of 日本人論 way too often trumps critical sense and fact-checking in these instances... – Dave Jun 14 '11 at 16:02
+1 for stressing the importance of sources. I very much agree with Dave in this. Personally, I call it the "Cultural Blackhole argument". – wallyqs Jun 15 '11 at 0:24
@istrasci: thanks a lot for taking the time to type this up. Regarding the first bullet point (rest makes sense and only applies to usage in very specific instances): seems your teacher's claim is that pre-Heian (literature?) only has 4 colours (assuming one even considers white and black to be so). This is factually and verifiably wrong: to pick one example out of many, Asuka era's 冠位十二階 (more info on the Jp link), clearly uses 紫 or 黄 and predates Heian by a century... – Dave Jun 15 '11 at 6:38

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