Somewhat cryptic title, but a simple question.

I start with the (logical?) assumption that kanji makes writing Japanese shorter than using romaji. How shorter is it compared to English written in Latin script, on average? For example, how many pages would an average 100 page book in English (Latin) have in Japanese (kanji+kana)?

Are there some studies concerning this topic?

  • This is an interesting question, but it feels very speculative at best, and thus off-topic in my mind. – istrasci Oct 16 '13 at 19:31
  • Well, the answer is determined by many factors. As of yet, there do not seem to be any formal studies in English. Are you asking for how many kana on average, using kanji will save? Perhaps you are asking how much shorter Japanese is than the equivalent English? In the latter case, I recommend you compare Japanese classics with their English translation and English books with Japanese translations. Check these sites: Aozora Bunko and Project Gutenberg. You will probably need to conduct your own research. – user4060 Oct 16 '13 at 19:33
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    @istrasci I don't think this should be closed as off topic. There could very well be answers that aren't speculative. I find it hard to believe that there is absolutely no hard data on this subject. – Ataraxia Oct 16 '13 at 19:55
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    Japanese is definitely much more dense than letter-based scripts. Just look at what Japanese people post on Twitter. They can fit a complete story or two in a single tweet, while English speakers often have to split single sentences. – Igor Skochinsky Oct 16 '13 at 20:18
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    @Igor Skochinsky: I am afraid that it is not that definitive. Note that the question asks the number of pages needed to express the same thing in Japanese and English. You are comparing the number of characters between Japanese and English, but then a character in Japanese takes more space than a character in English on paper, so these effects may well cancel each other when we compare the number of pages. – Tsuyoshi Ito Oct 17 '13 at 13:50

This is not an answer, but I will post it in the hope that it may resolve part of your confusion. I am afraid that you seem to be mixing “shorter” in the sense that it uses less characters and “shorter” in the sense that it uses less area in typical typesetting (hence less pages in typical books, assuming that the size of a page is similar in books in English and books in Japanese).

I think that it is fair to say that text in Japanese tends to use less characters than the corresponding text in English, because the writing system of Japanese has more characters to choose from. However, for the same reason, characters in Japanese tend to be more complicated than those in English, and therefore characters in Japanese take more area when printed than those in English. Therefore, it would not be surprising if books in Japanese sometimes have more pages than the corresponding books in English.

Your comparison of the number of pages of novels in English and Japanese is interesting (from your comment):

I already did something on my own, comparing Anna Karenina, Crime and Punishment and Catcher in the Rye in Japanese and English (using Amazon book data). Interesting enough, the Japanese version of The Catcher in the Rye had more pages than the English one.

Although comparing three pairs of books is clearly not enough to draw any conclusion, what you observed may have something to do with the fact that Catcher in the Rye is originally written in English and translated into Japanese, whereas Anna Karenina and Crime and Punishment are originally in Russian and translated into both English and Japanese. I would try to see if the comparison gives the opposite results in case of novels originally written in Japanese and their translations into English.

I have been always thinking that there may be a tendency that text translated into some language is longer than text originally written in the same language. I do not have any evidence for this hypothesis, but if this tendency really exists, a hypothetical reason is as follows: A text (especially text in novels) in some language is often written in such a way that it is natural in that language, and probably natural text can often be concise. Translation tries to reproduce the content and/or the atmosphere of the original text in another language, which forces less natural way of using the language. Therefore I think that it is a plausible possibility that translation often sacrifices conciseness. Of course, this is just a hypothesis yet to be tested, unless someone has already thought the same thing and tested it. [Edit: PhoenixFox has already mentioned a similar point in a comment on user54609’s answer, so it is at least not just me.]


An alpabet has roughly log(60)~6bits informations and a Kanji has roughly log(3000)~12bits informations.

Here we assumed that every character has equal frequency.
More acculate estimates would be
-Σ((probability of a character X)×log(probabily of a character X)
(sum over every character X).
If all the character have equal frequency, this sum becomes to log(total number of characters).
If we include the space character into the sum above, the sum becomes smaller because the frequency of the space chacter in alphabetical texts is very high.

So a kanji character has as twice informations as that of an alphabet.
Since each kanji character has twice width as that of an alphabet, and English texts have many spaces, I estimate the total length of japanese texts would be 0.7~0.8 of English texts.

We assumed the very important fact that
'texts written in English and corresponding texts written in japanese have equal informations'
  • An interesting approach. If you also account for the typographic differences, kanji at times has up to approximately 4 times the width when characters like 'l' and 'i' are properly typeset and ligatures are utilized. – user4060 Oct 17 '13 at 22:34

In computer encodings, a kanji or kana usually takes 16 bits, not 8 bits, and even as much as 24 bits for really obscure kanji. In Weibo (the Chinese clone of Twitter, i.e. Evil Censorship Profiteer), Chinese chars count as two ASCII chars. Chinese (especially literary Chinese) is even more dense than Japanese though.

From a linguistic perspective (not a computer storage perspective), Japanese is very much the opposite of dense. This is mostly due to Japanese words being long:

緑 vs. green: 3 vs. 1 moras (グリーン is four...)

日本 vs Japan: 3-4 vs 2 moras

This is even more apparent when you factor in the agglutinative grammar of Japanese:

さゆりちゃんが来たので、とてもうしくなりましたね。 (22 syllables)

I'm so happy that Mary came. (8 syllables)

This is part of the reason why Japanese is spoken so quickly, and why it likes dropping pronouns so much. Nobody wants to say 私達は、あなた達と私達の昼ごはんをゆっくり食べました (36 syllables) for We ate our lunch with you slowly (8 syllables).

(Side note: earlier forms of Japanese were thought to have been spoken much more slowly, due to the fact that the phonology was complex, and things took less cruft to say.)

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    It also depends on the formality of the language and use of context. さゆりの来たことで嬉しかった (from 22 to 14 syllables). 午後、あなた達と一緒にゆっくり食べた (from 36 to 17 syllables). Still not as succinct as English, but certainly much more dense. Japanese allows pronouns to be dropped while English forces mandatory single syllable ones for clarity. I do believe you did an excellent job of answering the question otherwise. – user4060 Oct 16 '13 at 21:57
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    why it likes dropping pronouns so much. I was purposefully using an English style to show that expressing the exact same propositional content takes much mroe space. – ithisa Oct 16 '13 at 23:23
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    @user54609 I also find that the more subtle, literary Japanese takes much more English to translate properly. The best writings of either language are very difficult to express with equal brevity in the other. I've done a bit of casual translation of ranobe, so I can support this: (すっと通った鼻梁に日本人らしからぬ白い肌。-> She had white skin and a straight, piercing nose that clearly wasn’t Japanese.) Expressing that same content took more space in English in this case. I believe it is a matter of semantic density, not language, that determines the difficulty of translating the material. – user4060 Oct 17 '13 at 2:10
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    古池や蛙飛び込む水の音(11 characcters/17 syllables) vs 'An old silent pond, A frog jumps into the pond, splash! Silence again'(69 characters/17 syllables). – jovanni Oct 17 '13 at 3:53
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    @jovanni: you are interpreting the poem, not translating it. A translation is old pond / sound of water after frog jump (10 syllables). In any case Classical Japanese was historically spoken slowly,necessitating even more abbreviation:youtube.com/watch?v=5jEWDiPlxXU – ithisa Oct 17 '13 at 11:07

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