Japanese Culture & Photography
2 min readJul 14, 2021


Why is green, blue in Japan?

Ao Umi (Blue Ocean, Not Green)

Have you ever wondered why green (midori) is blue (ao) in Japan?

In Japan, Japanese people wait on red, go slow on yellow, and go on “blue”.

Before 1930 the word for green was Midori. However, it was 1930 in March when the first traffic light was placed in Hibiya and it was then where the press (newspaper at the time) used ao to describe the color. The reason for this was because they felt that people would prefer it to be described as blue. This is what I learned from a Japanese friend and various Japanese sources.

On 1947, the word ao was used in law to describe green light.

After time passed, there was more popularity in the word ao which is still used this way even today.

Ao Meaning

Japanese people used the word Ao to describe a vivid/bright green. It can also be used to imply that the thing is fresh or young as well.

Ao cannot be however, be used to describe a dark green or an old green.

Words like 青葉、青海苔、青虫、青汁、青臭い、and 青春 all use the color blue.

(Starting from the left Aoba (green leaves), Aonori (green seaweed), Aomushi (green catapillar), aokusai (immature), seishun (youth))

For green leaves, it is used to describe fresh or new green leaves. Green seaweed on the other hand, is used to imply that it is fresh and tasty.

Caterpillars use ao to describe their youth before transforming into a butterfly. Aokusai is used negatively to describe immaturity. (kusai means stinky)

Seishun is composed of the words blue and spring. Japanese people like to think of a persons life time in seasons. Spring is when they are a child, summer is when they are an adult, spring is when they have a family and older, and finally winter is when they have become grandparents. Basically it is saying that they are young twice in one word.

Have you heard of a Dagashiya? It is the name of an old Japanese candy store. I talk more about the brief history and some popular snacks that you can buy there.




Japanese Culture & Photography

Japanese culture, food, sightseeing spots, and photography. Tokyo based Asian American professional photographer born and raised in Hawaii.