I use an app called 漢字検定DX to practice kanji more specifically. It will show a kanji and ask what the radical is, giving a list of four options. Multiple options are present in the given kanji, but only one answer is right. Is there some sort of rule that makes certain radicals more important than others? Or are some not radicals? I don’t even understand how to answer the questions, so I’d like to know what exactly it’s looking for. I attached picture of a question it asks as an example.
This is quizzing you on the traditional Japanese/Chinese “radical”, which is rather different to what WaniKani calls a “radical”. In the traditional meaning of “radical”, each kanji has exactly one radical, and there are 214 of them in total. All the other components of the character are not radicals. Personally I think it would have been less confusing if WK used some other term (like “component”) to make it clearer that what it’s teaching you is not actually a radical.
Knowing the radical was useful for things like looking up a character in a paper dictionary, which ordered all the characters by radical. Arguably knowing traditional radicals is not very useful these days and not worth directly studying.
The right answer here is 4, incidentally. For characters with a left side component, it’s usually the radical. But if you care about knowing the traditional radicals there’s going to be a certain amount of just memorising involved as well as picking up common patterns.
This Tofugu article is a good summary of the traditional radical system, what the radicals are and how to figure out what the radical for a kanji is or is likely to be.
Thank you so much! I will actually need to use a paper dictionary, so that makes everything so much easier for me. The vocabulary WK uses definitely misled me.
Just to be clear, a paper kanji dictionary. Paper dictionaries for Japanese vocabulary wouldn’t require you to know radicals.
As an aside, you don’t absolutely need to know the traditional radical to look up a kanji in a paper kanji dictionary either, since most of them also index by stroke number, reading, etc… so if you know something about it you’ll probably be able to get to its entry. And you can usually just take a guess at the radical if you want to try that way too.
That’s usually how I look up an unfamiliar kanji on Jisho.org too, click “radicals” and select the one I think it is. It lets you put more than one to narrow it down even more, and orders results by stroke count. It’s pretty fast. (of course, cut and paste works too, but sometimes it’s in an image or something else not cut/pastable)
Though that’s the WK style of radical look up, where “radical” means “part” basically.