Word of the Week: 青信号 (ao shingō)

Posted: 8th March 2022

Hello again and welcome to the second round of the Ippo Ippo Japanese Word of the Week!

This week's word is...


あおしんごう / ao shingō

This is the Japanese word for "green traffic light": simple enough, right? Well...

The Colour 青 (ao)

青 (ao) is an interesting word sometimes described as untranslatable into English and many other languages. While the first result in a dictionary may read "blue" or "azure", 青 (ao) is in fact used to describe the colour of grass, vegetables and fruit such as apples. This overlap between English blue and green leads to 青 (ao) sometimes being called "grue" by linguists.

While this may all sound somewhat bizarre, it's actually quite common for different languages to have slightly different concepts of colour. There has even been research suggesting that there is an order in which languages historically gain words for colours, with white and black being the first to be named, followed by red, followed by green and yellow, then blue, then brown, then purple/pink/orange/grey. In other words, while we take the idea of colours for granted, our words for describing them are often newer than you might expect!

The History of 青信号 (Ao Shingō)

So: why is the colour of traffic lights called 青 (ao - green/blue)? After all, Japanese does have two words that mean exclusively green: 緑 (midori) and グリーン (guriin).

Part of the answer for this is that both of these exclusively "green" words are newer additions to the Japanese language, 緑 (midori) originating in the Heian Period (794-1185 CE) and グリーン (guriin) being a more recent import from English. Despite 緑 (midori) having been around for a while, it didn't really gain traction until after World War II - well after traffic lights were introduced back in the 1930s. Therefore, as 青 (ao) became more commonly used to mean "blue" and 緑 (midori) for "green", some people started to complain about the accuracy of the term 青信号 (ao shingō) .

Are Japanese Traffic Lights Actually Blue?

If you visit Japan today, you are unlikely to spot anything unusual about the traffic lights. However, look a little more closely and you may notice their colour is *ever so slightly* different from what you're used to. This is because in 1973, the Japanese government officially mandated that traffic lights be made the bluest shade of green possible that was allowed under international traffic light conventions.

This change not only placated those who had been complaining about the term 青信号 (ao shingō) - it also allowed some of the history of the Japanese language to live on in everyday life, including as a slight pain in the neck for those learning Japanese from scratch!

Did you ever think you could learn so much from just the word for "green traffic light"? I certainly didn't!


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