I know reading but not whether it is onyomi or kunyomi

[anshbansal]

As I go through vocabulary I see a common problem with many things. I know the reading of the word (because I repeated it many times over time) but I don’t know whether it is onyomi or kunyomi reading. The problem this causes is that many of times some words’ reading mnemonic says you already remembered X reading now use that. What to do in such a case?

[Leebo]

This is a pretty normal worry, and it goes away with experience. It’s understandable to feel like it didn’t really sink in. However, since there are constraints on what can be an onyomi and what can be a kunyomi (for instance, if something is more than 2 mora in length, it cannot be an onyomi) you start to just recognize them without even needing to be told which one it is.

[AmericanLion]

Please see this thread from last year. There is a userscript you can install that replaces kanji “reading” with kanji on’yomi or kun’yomi respectively in Wanikani. Also, the unofficial Android app “WK for Wanikani” does the same.

Install third-party scripts and apps at your own risk, but as a user of both, I can say there is little risk and much to benefit. For me, it definitely helps knowing which ones are on’yomi and kun’yomi. I have space in my brain to hold that info for a lot of items and I feel it really helps me to remember things better, and will probably get you in step better with people in traditional Japanese language courses and native Japanese speakers. If they mention which reading they are talking about specifically for a kanji, you’ll be more easily able to know that info.

How do you know when to read on'yomi or kun'yomi?

Is there some sort of special trick to it, or does it just vary? I know that people have said that with higher levels and practice you can get a feel for it, but I was just wondering if there was a quicker way to learn and distinguish.

[VictorLino]

There’s a general rule but to that rule there are always exceptions. I know I messed up good early on for the several readings.

If you see a lone kanji, the WK will ask for either it’s on’yomi (pink) or kun’yomi (purple) reading.

So if it’s a vocabulary word (purple words) made of just the kanji, or kanji + kana, like 女 or 女の子 then the reading it’s probably kun’yomi, so

女 - おんな (onna)
女の子 - おんなのこ (onna/no/ko)

If it’s made of two Kanji, like 女子, then it’s probably the on’yomi readings so:

女子 - じょし (jo/shi)

So, two or more kanji - onyomi
Lone kanji or kanji + kana - kunyomi.

Don’t worry too much about it, the wanikani will give out some tips in how to recognize when it’s the correct readings, and you will start to see some patterns, just don’t forget that there are always exceptions to this rule.