Generally, on'yomi is the compound reading, also known as the Chinese reading. かい(kai) is the on'yomi and is used in words such as 海外(kaigai)
Kun'yomi, on the other hand, is the individual reading or the Japanese reading. In this case, うみ(umi).
Okay, so to make sure I understand the on’yomi and kun’yomi concept right: if you use ocean in compounded words then you use kai and otherwise umi? So after kai there must always follow another word?
Thank you!
Or if there is something before it.
And with 海 there are also quite a few compounds that use the Kun-Yomi like 海亀 (umigame) and some that have a completely different reading like 大海原 (oounabara), 海豚 (iruka) etc.
Usually you aren't advised to blindly learn kanji-readings but to study vocabulary and how it's written.
@JKF Yes but just generally, it isn't a 100% consistent rule as another user has pointed out
海 Kai or umi?
Hello, I’m wondering if you see this kanji, which I believe means ocean, do you pronounce it as kai or umi?
I’m not sure but maybe the pronunciation depends on if the kanji stands alone then it’s umi and if there is something more for example if you say “deep ocean” then you say “kai + the japanese word for deep”? Is this what onyomi & kunyomi is about?
Thanks!
-JKF