Japan’s traffic lights may confuse visitors because the signal that tells drivers to go can appear blue instead of green. However, this unusual color is not caused by faulty equipment or different traffic rules. The explanation comes from the Japanese language and a tradition that has existed for centuries.

In Japanese, the word *ao* historically referred to both blue and green. Although *midori* later became the separate word for green, older expressions continued to use *ao* when describing things that are clearly green. Even green apples and bamboo can still be associated with the traditional term. Traffic lights followed the same linguistic pattern, with green signals commonly being described as blue in everyday language and official documents.

When Japan introduced modern traffic lights, the go signal was green, but people continued calling it blue. This created an interesting difference between the actual color and the word used to describe it, eventually attracting attention from visitors unfamiliar with the tradition.

According to *Atlas Obscura*, the Japanese government addressed this unusual situation in 1973 by choosing the bluest shade of green legally permitted for traffic signals. This compromise helped bring the traditional wording closer to the color people could see, explaining why some Japanese traffic lights appear turquoise or slightly blue.

Despite their unusual appearance, these signals have exactly the same purpose as green traffic lights elsewhere: telling drivers they may proceed when it is safe. What seems like a small difference actually reflects Japan’s long linguistic history and shows how cultural traditions can influence even everyday objects.