ルビ付き和訳は英文の下にございます。/ The Japanese translation is below the English text and is fully rubied.

Why does “ruby” mean “furigana”?

  1. What is furigana?
  2. What is “ruby”?
  3. How “ruby” came to Japan and became “rubi”
  4. The meaning of “rubi” today
  • Japanese translation (和訳)


1. What is furigana?

An image to show an example of “ruby” in the horizontal text
In simplified news for learners of Japanese and young people, they often put furigana on Chinese characters. Image by NHK

Do you know “furigana”? 

When you read a Japanese text, you sometimes see a small hiragana near a Chinese character. It is usually placed above the Chinese character in a horizontal text. Those hiragana indicate the pronunciation of the Chinese characters and are called “furigana”.

“Furi-gana” is a compound word of the “masu” stem of the verb “furimasu” meaning to assign and “kana” meaning hiragana or katakana. Therefore it means assigned hiragana or katakana.

Traditional Japanese writing is presented in vertical text. In this case, furigana is placed on the right side of the Chinese characters. 

2. What is “ruby”?

An image to show an example of “ruby” in the vertical text
This is an example of furigana typeset vertically. The furigana on the side of the kanji meaning happiness reads “saiwai” meaning happiness.

“Rubi” means furigana, but I didn’t use the word when I was a student. I first noticed when my boss used it while I was working as an editor. We used the word in communicating with typographers, too. 

So I thought it was a term used in the publishing business, without knowing why.

Later, I learned to type in Word and found the function to allow me to put furigana for a Chinese character. They indicate this function as “ruby” in English like a jewel. 

Since “rubi” and “ruby” sounded very different to me, I thought they had nothing to do with each other. I was wrong.

3. How the English “ruby” became “rubi” in Japanese

An image of a 19th century Japanese newspaper with ruby
The photo is a part of the first issue of Asahi Shimbun, Janaury 25, 1879.

In the 19th Century, British typographers referred to different font sizes by specific names. For example, type with a height of 6.5 point was called “emerald”, 5.5 point “ruby”, 5 point “pearl” and 4.5 point “diamond”. They used these words for interlinear annotations.

Turning to Meiji Japan (1867-1911), Japan received an influx of Western culture. As one example of the Western influence, newspaper publishing and letterpress printing began. Some publishers typeset furigana on Chinese characters so that people without higher education could read their articles and advertisements. 

The size of a font in newspapers was shown with a number and a unit “goo (号)”. For example, they used 5-goo for the main text and smaller 7-goo for furigana. 

And the 7-goo was very close to the British “ruby” size. So they first referred to the size as “rubi”, but then the meaning changed to indicate typeset furigana of any font size.

By the way, in American English, they called the size of “ruby” “agate”. We don’t know why that word didn’t enter Japanese, but as a retrospect, “rubi” is better since it is shorter.

4. The meaning of “rubi” today

In today’s Japanese, “rubi” is just another name for furigana. But there is a hint of history in the “professional” atmosphere around it.

[End of the English post]


  1. とは?
  2. 「ルビ」とは?
  3. えいの「ルビー」からほんの「ルビ」へ
  4. 現在げんざいの「ルビ」


1. とは?










のちにワード文書ぶんしょ使つかかたならったとき、かんけられるのうりました。こののうは、宝石ほうせきのように「ルビー Ruby」というえいしめされます。


3. 「ルビー」がどのように「ルビ」となったか







4. 現在げんざいの「ルビ」



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