About Numbers and Counting

The vocab lessons say that kanji typically use the kun’yomi reading when alone in a sentence. Numbers are an exception: all besides 4 (よん) and 7 (なな) use on’yomi.

Yet I’ve definitely heard the on’yomi reading for 4 (し) when people count. I don’t recall if I’ve heard しち for 7.

So which is “correct” when counting? Is either acceptable?


For 4 and 7, either onyomi or kunyomi can be used in counting, which makes them different from the other numbers when counting the pure numbers alone. So, the sentence describing the exception might be a bit hard to parse, but I think it’s not inaccurate.

It could definitely be worded more clearly though.


Pretty much. I have noticed a tendency to use よん when counting up and し when counting down but it’s by no means universal.

I also come across なな far more frequently than しち but I think that’s more because it’s easier to say things like ななじゅう than しちじゅう. And I don’t remember ever hearing しじゅう for 40 but I don’t know if it’s never used or it’s just me.

Also, I believe しち is used in numbers when it comes to telling the time right rather than なな? and よん rather than し also although I believe when I saw earlier was that the ん is dropped so it’s よじ instead of よんじ(for 4 o’clock).

So 5 o’clock - しちじ, 4 o’clock - よじ.


And く for 9.


Though just to be clear, that’s just an alternative onyomi, not the on vs. kun distinction.

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I also thought people didn’t use しち and し for じゅう and stuff, but apparently it’s up to the speaker.

I also learned, if it’s correct in the first place, that the reason words following よん have different rendaku than さん is because it used to be from when し was used and they just changed it to よん but didn’t change the rendaku?

Surely Leebo knows.

Also 四分 can be よんふん or よんぷん? But now I’m talking about rendaku instead of numbers.

I also learned the numbers from 1 to 10 with し and しち (from a Chinese friend who knew Japanese) before I learned Japanese, so it’s stuck like that.

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I don’t think that’s really the case. The logic behind rendaku is mainly phonetical (as in what sounds native Japanese speakers are comfortable with saying and not), so usually there is not this type of “this is a 4 (concept), and 4 doesn’t rendaku” way of thinking.

Usually when Japanese folks discuss these differences the reasons given are either historical, use frequency or accent wise.

https://www.ytv.co.jp/announce/kotoba/back/2401-2500/2456.html (jump to ことばの話2457)

For example, 3階 being サンガイ and 3回 being サンカイ is attributed to the fact 3階 was already in use in the Nara period, appearing in the 日本書記, while 3回 only became common in the Edo period, about a thousand years later.
Perceptions on what is comfortable to pronounce had naturally changed over the years, but words don’t change that easily once formed, so the old ones sometimes stick as they were.

The above article also briefly touches it, but the fact the rendaku perception changes over time is also often brought up by natives, with older generations commenting on how young people nowadays say things such as 3フン and 4フン, which they were not used to.

For the “3 does rendaku but 4 doesn’t” pattern specifically, it’s usually said that this “let’s make シ into ヨン” thing is very recent linguistics-wise, such as early 20th century. So when the ヨン+フン、ヨン+カイ、ヨン+ケン and etc happened, people were already comfortable with not rendakuing after ん. The fact it was「シカイ」is not really that relevant.


Sorry, that’s not something I’ve ever looked into.


Also, so did the literal sounds used in the language