How to tell if a Jukugo word uses kun'yomi instead of on'yomi?

I know the rule with body parts so something like 手元 is てもと, but I was wondering if someone could elaborate on why other vocab words would use kun instead of on.

For instance my brain always wants to call 大空 as たいくう instead of おおぞら, as it uses kun’yomi despite not being made up of any body part or animate object kanjis.

I do EN->JP, used to be KaniWani, but now I’ve moved to Anki. The easiest way to create Anki deck for this, is

So, I don’t think whether it has to be Kun or On reading at all, just knowing that such vocab exists.

But if I have to guess the reading of Jukugo word, yes, I do guess twice.

You can have any combo, on-on, kun-kun, on-kun, kun-on… And there’s not much you can do but memorise the words.

This is where speaking helps a lot.


If you encounter a completely new word in reading, all on’yomi is your best bet.
The most efficient way to memorise the exceptions is probably to use them in speaking.

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Listening too. So, get some speaking/listening materials quick.

There are Anki decks for this, if you are interested. Of course, you might just speak it, or get some native listening materials instead.

From here. By hinekidori.

I recommend you eventually listen to something, though.

You should get a feel for it after a while. If the word is very common in spoken Japanese then there’s a chance that it survived the appropriation of Chinese characters and it will use kun’yomi readings.

I think the thing about 大空 is that it’s not a compound kanji, but a compound word. It is a slightly difficult distinction to get. I guess 大い isn’t taught as a word because no-one really uses it any more except as the adverb 大いに (ha ha ha like that ever stops WK, but joking aside it’s so archaic even my IME won’t produce it), but 大空 is a contraction of 大い空. It’s two words that have been compounded into one, rather than one word that requires two kanji. So it uses the readings of the constituent words, which is kun’yomi in both cases.

That doesn’t really help with how you know the difference, but hopefully it helps with understanding why there are differences.


No thats actually pretty helpful. I think I understand now that there aren’t really catch all rules, especially since Japanese seems to be a language thats had a lot of linguistic changes and evolutions over the ages relative to other languages.

It is a matter of experience, there isn’t not much you can do about that. Speaking is certainly the best way to memorize such words, but reading also can helps, if you don’t have access to people you can talk.

Does this mean that we shouldn’t care about which reading is the kun or which is the on? Until now, I have just focused on knowing the reading of vocab and understanding which readings a Kanji has. Am I doing it right?

Thanks in advance :slight_smile:

I wouldn’t go so far as to say don’t care. But until you get your legs under you don’t worry about it as much as just remembering the words.

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As always, I appreciate you taking the time to help! :wink:

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