For most 漢字 with multiple 音読み, there appears to be a fairly reasonable link between the sounds, and fairly minor drift, such as with 聞 being モン or ブン.

Some 漢字, however, appear to have completely unrelated 読み, the prime example being 回 with カイ and エ. If it was just that one it could be readily dismissed as an historical accident, but the カイ/エ 読み is shared with the also visually unrelated 会 and friends.

So the question is; what's going on here?

Update: As l'électeur points out, this might be explained by the size of China, but if so: Why don't more 漢字 have these apparently unrelated 読み?

  • Hint: Size of China.
    – user4032
    Commented May 7, 2015 at 14:40
  • 7
    In fact, エ(ヱ, we) and カイ(クヮイ, kwai) are related. The link between their vowels “e” and “ai” is obvious. The initial part is not so evident, but their relation is analogous to that of モン and ブン: the original more voiced consonant became less voiced. Since Japanese did not have velar fricative consonants, it used /w/ and /kw/ to emulate.
    – Yang Muye
    Commented May 7, 2015 at 15:59
  • Read the "onyomi" section in the wikipedia entry for "kanji".
    – red shoe
    Commented May 7, 2015 at 16:50
  • @YangMuye I'd be interested to know more about this. Would you post your comment as an answer and maybe elaborate?
    – Earthliŋ
    Commented May 7, 2015 at 16:50
  • 1
    @Yang Muye, Japanese also struggles to emulate the /x/ you find in 会 and 回 (both 'hui' in Mandarin). It loans often as /k/ (as in 花), but also as /w/ (as in 绘, which then became え when Japanese lost ゑ as a distinct sound)
    – sqrtbottle
    Commented May 7, 2015 at 20:34

2 Answers 2


Taking up the chance to talk about "Unrelated readings" because I get the chance to talk about both Japan and China's phonologies in the past.

It's well known that even amongst 音読み, there are the types from different Chinese regions and times.

漢音:Hanyin, from the original middle-chinese pronunciations

呉音:Wuyin from SE China (state of Wu)

唐音:Tangyin from Tang China around the late 1500s

慣用音:These are actually Japanese corruptions of Chinese readings, not used anywhere in China. コク for 石 is one example, which was corrupted from ジャク (the approximation of Hakka's pronunciation, shak)

There are others, usually taking name from the Chinese state that they originate from.

General sense

When Japanese first borrowed Chinese character sounds (漢音), Chinese had a slightly different phonology to now. Firstly, /h/ was /φ/ (same sound as ふ nowadays, which never changed). Usually, Chinese's /x/ (pinyin: h) was borrowed as /k/, but sometimes as /w/. Examples of this are 会 (ZH: hui JP: kai, e) and 絵 (ZH: hui JP: e). Tones weren't borrowed at all.

They also copied more closely the ~ao vs ~ou distinctions in Chinese (compare 道 and 豆 ZH: dao, dou JP: dou, tou). Japanese dictionaries kindly list pronunciations of kanji that have changed. Dictionaries tell you that 道's reading of どう actually used to be だう.

There are too many rules to list all of them out. Common ones are those above, and final 〜う instead of ~ng found in Chinese varieties (such as 同{どう} ZH: tong).

Both Japanese and Chinese (taking Chinese as one language) have since changed, but there are enough varieties of Chinese that it's usually clear to see which language / dialect is the divergent one (like how Mandarin has no -p, -t, -k final consonants anymore)

In the purest sense

"Unrelated" on'yomi are almost always going to be 慣用音. 良 has a fair few, such as ら, which sound nothing like the Chinese liang used today. This is because they actually diverged from the Chinese loanwords into something distinctly Japanese, and is also why they're so uncommonly used in actual words (I can't think of any examples of 良 as ら other than in names).

Other reasons

One thing to note is that sometimes the Chinese itself was unclear when Japan borrowed the sounds, even without different languages or bad transliterations. There are kanji that have readings with /m/ initials, and some with /b/ (文聞無望亡 to list a few). These are all taken from the same Chinese regions and time, but people probably couldn't say which it sounded more like, and use both /m/ and /b/ readings these days (and Chinese has all 3 starting with /w/).

So, the reason why kanji are unclear are usually:

  1. Japanese borrowed them badly in the first place because it didn't have the right sounds to say them properly (eg 花{か} ZH: hua)
  2. Japanese borrowed them properly, but then its phonology changed and now doesn't resemble as much (eg 絵{え} from ゑ ZH: hui, said like "hway")
  3. Chinese was in a transitional phase when Japanese borrowed them, so Japan took a few pronunciations all from the same Chinese dialect (eg 聞, read as ぶん and もん)
  4. Japanese borrowed properly, and just corrupted them (eg 良{りょう} as ら)
  • sqrtbottle, some points to note. Re: /m/ vs /b/: Chinese is a collection of languages, and many of them retain /m/ or /b/ where modern Mandarin has /w/. See this entry for 亡, for instance. Re: 良 read as ra: Old Chinese is reconstructed as /raŋ/, suggesting that the Japanese ra reading is not a corruption. See this entry for 良. Commented Mar 28, 2016 at 18:05
  • Re: JA kai vs. e: Modern Mandarin h appears in Middle Chinese as either /h/, /k/, or /ɣ/. A reading of /hwaj<sup>H</sup>/ would likely be imported into Japanese as /wai/ or (depending on vowel flattening) possibly as /we/, and indeed the older version of the e reading for 会 is we. Note too that, even in modern Mandarin, 会 (or traditional 會) can be read as kuài as well as hùi. Commented Mar 28, 2016 at 18:24
  • I don't think it's accurate to say that Japanese borrowed [the readings] badly. Japanese 花 ka is from older kwa, which derives in a straightforward manner from Middle Chinese /xwa/ (where the IPA /x/ is a harder sound than English /h/, like the ch in Scottish loch). Also, different on'yomi for a single character reflect not a transitional phase in Chinese, so much as borrowings from different dialects and different times. "Chinese" is a useful fiction -- there is no single Chinese language, but rather a collection of related languages, that (mostly) share the same writing. Commented Mar 28, 2016 at 18:28
  • Re: the readings for 聞: It's worth noting that modern Min Nan Chinese as used in Fujian and Taiwan has a reading of bûn, while Cantonese has man<sup>4</sup>, suggesting that the two Japanese readings might source from the ancestors of these two modern Chinese languages. Commented Mar 28, 2016 at 18:50
  • I wanted to mention about the tone 入声, which was somewhat borrowed as a second sound, one of キクチフツ. ja.wikipedia.org/wiki/%E5%85%A5%E5%A3%B0
    – Keita ODA
    Commented Mar 28, 2016 at 19:30

In fact, it is perfectly normal that the 音{おん}読{よ}み of a 漢{かん}字{じ} seem to be unrelated. Indeed, the 音{おん}読{よ}み of the 漢{かん}字{じ} were imported from China at different period and from different regions.

There are three kinds of 音{おん}読{よ}み:

  • 漢{かん}音{おん}: Spread by the monks who studied in Ancient China around the 7th, 8th century.

  • 呉{ご}音{おん}: More ancient than the 漢{かん}音{おん}, those readings were imported from the Wu region of China. That lecture is very frequent in buddhist terms.

  • 唐{とう}音{おん}: Those lectures were introduced at the end of the Heian period. They are the most recent of the three. During the 室{むろ}町{まち}時{じ}代{だい} this lecture was called (唐{とう})宋{そう}音{おん}.

  • What are the kinds that are not the "three main kinds"?
    – Earthliŋ
    Commented May 7, 2015 at 15:03
  • @Earthliŋ, during the Muromachi period the 唐音 was referred as (唐)宋音. Even if it is the same its name differs. That's the only case that I didn't mentioned because I think it's not relevant. But in real life there are three kinds of onyomi and I never heard of any other. I can possibly remove the main to remove the ambiguity. Commented May 7, 2015 at 15:10
  • Oh, I see. I asked because the 新漢和大辞典 names 漢音, 呉音, 唐宋音, 慣用音, the last being for all "other" 音-type readings, like コク for 石, which is neither 漢音 (セキ) nor 呉音 (ジャク).
    – Earthliŋ
    Commented May 7, 2015 at 16:37
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    It is the 音読み of 斛 and 石 is the 当て字 for its simpler shape.
    – Yang Muye
    Commented May 8, 2015 at 1:08
  • 3
    It's got nothing to do with the shape -- both were the name for a historical unit of measure in China and Japan. They were used interchangeably in both Japan and China as hu (斛) or dan (石). They used to be equal in the Tang Dynasty, but then one hu became equal to about 5 dan in the Song dynasty (source: zh.wikipedia.org/wiki/%E6%96%9B). It's not ateji, it's just a historical interchange between the two characters that meant the same thing at one point
    – sqrtbottle
    Commented May 8, 2015 at 16:31

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