Radical error for 究 (Research)?

I’m currently struggling my way through Level 8, and I noticed what seems like an error to me.

Compare the radical decomposition for Sky to that of Research.

They both clearly have the same radical component on top, but the page for “Sky” identifies it as “Roof” + “Legs”, while the page for “Research” goes with “Hole”.

I’m only a lvl-8 newbie, but the “Hole” radical on “Research” seems wrong to me, as the radical–upon close inspection–is clearly NOT “Hole”.

Not a big deal, but it threw me off while I was trying to puzzle stuff out. If I’m off-base, please set me straight, and if it’s a mistake, please let me know which channels I need to go through to request a fix.

Thanks much!


I definitely see the resemblance between the “Hole” in the Research kanji and “Roof + Legs”, but I think this is just a case of a radical changing shape slightly when it’s in a certain position in a kanji (a lot of radicals do this.) The Hole radical just so happens to look an awful lot like the Roof + Legs combination when it’s the top radical of a kanji, such as in the Research kanji.


I think the shapeshifting radicals phenomenon is something that WK doesn’t explain super well when it pops up.

Btw, you might have even noticed it already, but the chinese character is much closer to “hole + something” than “roof + legs”, radicals do change shape a lot, the only reason wk isn’t using the hole radical for sky, is that you learn “hole” on level 8

It’s hole, etymologically speaking anyway. It represented the concept of cave-dwelling.

The fact that it gets written with a “hane” (the little upturned part on the right side) in Japanese is confusing for sure.


For both and , simplified Chinese version use 穴 at the top; and the etymology is the same for both languages.

Anyway, radicals can morph, and Japanese people have their sense of aesthetics.

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I appreciate that the “hole” meaning may in some way be in alignment, but the names given to the radicals in wanikani don’t always have any relation to their actual meanings (for example,ヨ = “wolverine”). There is sometimes an overlap between the name and the meaning, but wanikani doesn’t make it clear when that’s the case; they seem more interested in burning the shape into your memory so that it can be used as a visual mnemonic when recalling the little story that describes a kanji. In the case of “research”, they seem to be breaking their own rule, as the radical–morphing notwitstanding–is an exact match for “roof” + “legs”, which means that they’re sort of breaking compliance with their own system. If they had just gone with “roof” + “legs” for both kanji and told a different story in each case there would have been no harm on my end–I would have learned both kanji without confusion–but with the current state of things I have an extra wrinkle complicating my efforts to learn.

At any rate, I’ve emailed the crabigator team with my notes, and while I have every confidence that they will agree with the replies you guys have posted, you can’t blame me for trying. Thanks much.


Hey shmax71!

The Crabigator team got your email! I’ll let the content team know about this to see what they might have to say about the subject. Thanks for the bringing it up. :sunglasses:

-Nick at WK


I’m actually on level 8 too and was a bit confused about this as well. I would be interested in hearing what the content team has to say. Thanks for bringing this up.

edit: I looked up the radical components on a Japanese website and it says for sky it’s 穴 + 工

Other websites say 究 also uses 穴. So I’m wondering if Wanikani wanted use to use the radicals we learned in level 5 before teaching us a new radical which is in a later level?
I think for the sake of memorization, maybe WK stretches things? For example 穴 is made of the roof radical and eight, but the mnemonic uses a volcano.

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I received a reply from the moderators:

I wanted to let you know that we looked into this and decided to move the “hole” radical from level 8 down to level 5, and then have the 空 use the “hole” radical like other visually similar kanji have.

This has been moved to our list of ‘to dos’ and should be completed in the next few weeks! Thanks again.

I don’t exactly remember the details of the issue, but for those that do, there you have it.

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