The vagueness of ō annoys me. Is there a rule to know how it works?

When there’s a bar over a vowel the vowel is usually doubled up but not in the case of ō. Ō seems to mean either a doubled up vowel or in some cases an う. Is there a rule I can use to distinguish whether its one or the other. This isn’t an issue on Wanikani but I notice so many online learning resources as well as textbooks use this ō but it’s never clear what it represents so I can’t tell by reading it whether my pronunciation is correct.

Here’s an example where ō represents う
Father = Otōsan = おとうさん

Here’s an example where ō represents お
Big = Ōkī = おおきい


The general rule is that おお is used in words that use kun-yomi readings (like 大きい and 氷) and おう in words that use on-yomi readings.


The thing is, too, the pronunciation for おう and おお are generally the same. They’re just two different written ways of turning the お into a long vowel, which is why they’re not differentiated in romaji.

The real fun part is when you have long vowels in proper nouns like Tokyo or Hokkaido, because then the long お isn’t even marked in romaji at all.


Even better is if you encounter older text where Tokyo was romanized as Tokio. There’s also times when both おお and おう are romanized as oh like in romanized title of the movie Jin-Roh. Just to make things even more confusing. :expressionless:

Romanization is such a subjective system based on who makes the rules and it’s why I really hate when otherwise good resources use romaji over kana.


Your answer makes sense. That’s the way I figured. Just annoying haha.

Really they have the same pronunciation? I always get nagged at for mixing them up. I am certain they’re pronounced differently. When I pronounce father as otoosan my friends will repeat it slowly, it’s supposed to be oto ‘u’ san.

Huh, that’s the first I’ve heard of that. Even on Forvo they don’t pronounce the う separately. They just hold the お longer, which is also how I was taught.

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Not technically. There is a subtle difference, but at normal talking speed they will essentially sound the same. For example, I can tell a subtle difference between the way the おう in お父さん and the おお in 大きい are pronounced in the WK audio. I can hear a slight う sound in the former.

I don’t really hear the difference – of course, that’s not to say that it isn’t there, but more that, like you said, it’s subtle enough to sound the same. I was personally taught in my college course to pronounce the two the same way.

That being said, though, @Bag_of_Dragonite, were your friends emphasizing the う more than what’s in the WK recordings? I’m curious about that now.

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I wonder if a lot of it is also dependent on speaker. With one of the Japanese teachers I’ve had I could clearly hear a slight う sound when she was pronouncing words that have おう. :man_shrugging:

I’m thinking this might be it as well. Maybe it’s kinda like how some people will still emphasize the う in at the end of です and ます? :man_shrugging: indeed.

Romanization has made me scream so many times. The Modified Hepburn system is one of the reasons it took me years to figure out how to write 東京 correctly.

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It’s just a spelling difference, not a pronunciation difference.


In standard Japanese or always?

Is anything ever “always” with Japanese?


Fair enough. You know what I mean though. :stuck_out_tongue:

WK teaches standard Japanese so when I talk about how it relates to what we’re learning I’m just focusing on standard.

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See this discussion:う-pronounced-as-ou-instead-of-a-long-o

Can you listen to the お父さん audio? I swear I can hear a slight う in the pronunciation. But I fully concede now that it may just be my brain tricking me.

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Maybe you’re pronouncing it as closer to おとさん (without the long ō) and your friends are trying to emphasize that it’s a long ō by dragging out the う (which I have heard Japanese people do before).


Another reason to stick to traditional Hepburn romanization.

Maybe someone could explain to me how it is in any way useful to use the revised form with character that mean two things. The pronunciation is slightly different. It’s reductive.

おう = ou
おお = oo

Easy. I can see how it might be easier for people who know nothing about the language, because they are going to see おお and think it’s pronounced like an うー. But I don’t see why we should change a good system to account for the ignorant.