I am a bit confused about this. For instance, the word for “king” would be written as おう in kana, but the word for “ten days” would be とおか, right? What am I missing here? Is there a rule that I don’t know about?
It is mostly a historical thing. I haven’t really found a rule about it. Just memorize it.
In case of とおか、I think it is derived from とお(十) ten things.
There is also 通 which has the same kun’yomi.
That is all the ones I know from memory. Most of the times that long ō is written as おう、よう、とう、こう and so on.
The rule is “words that were once written as ～おほ or ～おを are now written as ～おお, while ～おふ became ～おう”. But yeah, unless you’ve got a master’s degree in Japanese etymology, “just remember them as you encounter them” is the better method.
Like @Saida said, it’s ～おう more often than not.
I think I’ve mostly seen おお when part of a kun’yomi reading like 氷(こおり) and おう when on’yomi like 人工(じんこう).
Just knowing that there is a solid etymological reason for the difference will help me sleep tonight. Thanks.
I can venture to guess that at least one of the dialects will pronounce the two slightly differently, perhaps?
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.