Red, Yellow, Blue. The traffic lights of Japan!

If there is one thing that most people will guarantee about anywhere, is that red means stop, and green means go. It is a simple lesson that we all learn way before we sit behind the steering wheel. So, what happens when you see a blue light instead of green?

Red, Yellow, Blue. The traffic lights of Japan!

If there is one thing that most people will guarantee about anywhere, is that red means stop, and green means go. It is a simple lesson that we all learn way before we sit behind the steering wheel. So, what happens when you see a blue light instead of green? As I said, it's a simple lesson that we all learn but in the case of the Japanese, they learn it as "blue" means go. To be honest, it is not blue, it's still green. But it is the very blue shade of green and the Japanese government have assured everyone that it is still green. So why don't they just use the green that everyone else knows so well? Because of the Japanese language!

Time for a quick history lesson, originally the Japanese language only included words for only four basic colours: black (Kuro/), white (Shiro/), red (aka/), and blue (ao/). So, there was no word for green, until the Heian period (794 to 1185) when the word Midori (緑) was introduced. Midori is the word for greenery but now used for talking about green things like a green car for example. But Midori is seen as a shade of ao.

Because of that, occasionally you see green things like vegetables labelled as blue. Picking up a Crispin apple (also known as Mutsu apples) and seeing it being labelled as ao Ringo (blue apples/green apples) can be very confusing. Other examples are ao yasai (blue vegeables/leafy green vegetables), ao nori (blue seaweed/green seaweed), and aodake (blue bamboos/green bamboos). Ao is also used when talking about people, for example, sometimes people talk about new employees by conveying them as being “green” as a new sprout. So, they can be called aonisai (青二才 / a blue two-year-old). So where does traffic lights come into this?

It turns out their traffic was originally like the UK's, as green as green can be. But with ao meaning blue as well as green, it confused Japan's official traffic documents as they still used ao to refer to green traffic lights instead of Midori. Now most of you may know that international traffic law decrees all “go” signals must be represented by green lights (look at united nation documents on agreed international roads sign standards or the Vienna Convention on Road Signs and Signals for example.) But the issue was Japanese linguists were objecting against the continued use of ao when they should have midori to describe the green lights. So, in 1973, the Japanese government finally decided to cooperate by making it mandatory that traffic lights need to use the bluest shade of green possible while still technically being green.

So be doing this, it allows for the Japanese government to have justification to use ao when talking about traffic lights while the lights are still green enough to satisfy international regulations. Now if you think this is the end of the blog, then I am sorry to disappoint you, but I have another topic to talk about. Pedestrian crossings!

Pedestrian crossings

Most pedestrian crossings will come across are automated or have a push-button like most UK's pedestrian crossings. But there are two other kinds of crossings that are found in Japan. The first kind is night time pushbutton crossings, these crossings are normal automated crossing during the daytime, but as pedestrian traffic levels drop during the night time, the crossing changes to a pushbutton crosswalk. To tell if a crossing is a night time pushbutton crossing, there is normally a sign saying” 夜間押しボタン式”, which translates to “Night Pushbutton Type”. The other kind is crossings for people who need a little longer to cross the street. For example, the disabled, seniors, pregnant women, injured people, those with children in tow, etc. These crossings are occupied with a white and blue sign of a person with a walking stick. When you push this button, the green light for pedestrians will last longer than usual.

Scramble crossings

There is another type of pedestrian crossing which is popular in Japan, Pedestrian scramble crossing which is also known as X crossing in the UK. These crossings stop all traffic temporarily, allowing pedestrians to cross an intersection in every direction at the same time. Most people know a famous scramble crossing in Japan, which is the Shibuya crossing that is known as the busiest crossing in the world with up to 3000 people crossing it at any moment. And wouldn't it be a shame if someone could hack the crossing's traffic lights?

Tokyo's jungle bird

But there's nothing unique about Japanese pedestrian crossing? Well, the sounds. If someone asked me what sound I will always remember, it is the call of Tokyo's jungle bird. But there is no "Tokyo jungle bird", the sound actually is of a cuckoo cry. Wait, a cuckoo??? This is Japan, not Australia, why is there a cry of a cuckoo? Well, it turns out Japanese pedestrian crossings use four different sounds to signal when to cross. So, therefore you can assign crossings to two types: melody and onomatopoeia.

Melody crossings use "Toryanse" which is a Japanese children's song, and "Common Frae the Town" which is a traditional Scottish folk song. Onomatopoeia crossings use the chirping of a chick and the cries of a cuckoo. Onomatopoeia crossings are seen to be safer so melody crossings are slowly being replaced by onomatopoeia crossings but if you are lucky enough, you will come across a melody.

So, as I am not in Japan right now, I thought the best thing to do is find some short clips of the crossings on YouTube:

Cuckoo cry:

Chick chirping:


Common Frae the Town:

I do advise listening to the whole of the video above as you can hear all the sounds quite clearly. The sounds of pedestrian crossings are a key part of the background sounds of Tokyo. And this is only the beginning of the sounds that are a part of my day to day life in Japan but are a window into my memories when I hear them in the UK.


This post may have seemed like an odd one to talk about. Like who wants to read a blog about something as simple as traffic lights? Well someone, who wants to know about a countries structure and culture. From a threat intelligence viewpoint, the most basic things are still really important to know about. And as a tourist and an overall curious individual, things like why simple things like traffic lights are different from what they are used to seeing, are interesting. Now for those readers who are interested in the cybersecurity side of me and maybe looking to come to BSides London, you might have noticed a little treat that I included about my London BSides talk. The only extra thing, I can say about it is all it takes to change the world is 10 seconds. So, it's time to say a big thank you to everyone reading this week's blog. In terms of next week, I have not decided what to do yet so here is a chance for anyone who wants a specific topic to say so before I choose from my pot of ideas. So, until next week, arigatou gozaimasu and sayōnara!