When to use "dai" or "tai' for 大

Hi all!

Just wondering if there is any trick or logic to knowing when to use which pronunciation for the 大 character when combined with other Kanji.


大事 - Daiji


大変 - Taihen

I just want to know if it’s unpredictable or not I suppose.



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It’s like 50/50. I can’t imagine a trick that wouldn’t just be rendered nearly useless by the exceptions involved.


Thank you I’ll use this idea!

Whenever you’re not using “oo”.


The accuracy of this hurts my soul.


I’ve always (like 6 months of study) thought it was unpredictable.

However, looking at your examples: could it be a question of the number of subsequent mora in the phrase? For example taihen where hen has 2 mora and daiji where ji has one mora. Likewise taisetsu, taikai However… daikon doesn’t fit the rule.

And exceptional readings (e.g. 大人, though that can technically also be read as だいにん, though I have never actually seen or heard that)

Ive come across it ONCE. Actually the reason I came across it was because a character pronounced it that way, which others found weird. In that case it wasn’t written in kanji either.

I just grumble whenever my wife corrects me.


In short, no. だい is the older Go’on reading (The first readings that came to Japan, through Korea, from the Wu regions originally, while たい is the Kanon, the later readings from the Tang dynasty.

Aside from various strata of importation, a number of Go’on readings were replaced with their corresponding Kan’on readings, but it was incomplete, so you get this mess going on without much reason behind why certain words are how they are.


Part of the reason some are “dai” and some are “tai” is to differentiate from homonyms. If a tai reading jukugo has too many homonyms, typically the reading will be dai, and vice versa. Maybe not useful for beginners, but could be once you get more advanced.

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It’s a little bit different, but you could try using this method:


I was also wondering

The problem is a visual one. If you look up audio material with these words your auditory memory might keep you right. Other than that I have no idea.

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