Slight confusion regarding 穴, 究 and 空

At level 8 the “hole” 穴 radical is introduced, which is then used in the kanji 究.

I was a bit confused at first because much earlier, at level 5, we are taught kanji 空 which, as far as I can tell, uses the same “hole” component except there it’s taught as a combination of “roof” and “legs”.

There are a bunch of other kanji introduced later on using the same 穴, always described as using the “hole” radical.

What’s the rationale for 空 being singled out here? It genuinely confused me at first because I thought I was getting things mixed up.


WK will take already seen parts and put them together in the form of a new radical. This is done in order to make the mnemonics not overly complex. Later on all you’ll get will be previously learned kanji as radicals. It’s a bit unfortunate, because it seems like it would mess up the mnemonics for earlier stages, but hopefully by that point you will have memorized that kanji without needing to think back to why it’s that.

1 Like

But the 穴 kanji itself is at level 20, so you haven’t encountered it already and won’t for quite a while. As such I would either expect the 穴 radical to be introduced for 空 and use that or just use “roof with legs” for the other kanji as well until you actually learn “hole” at level 20.

I feel like it’s a missed opportunity too because it’s pretty easy to tie the “hole” meaning to the “empty” meaning of 空 (which is actually taught at this point in the 空車 vocab immediately at level 5).

WK’s whole modus operandi is to teach you simpler elements before more complex ones but I sort of feel like they got it out of order here, the “hole” step is out of sequence.

1 Like

I would assume the wk team is trying to balance out the number of radicals you will be learning on each level. The first few levels are already jam packed compared to the later ones.

Fair point. It’s true that it must be quite the puzzle to come up with a decent progression for the first few levels without overloading everything with radicals.

1 Like

If I remember rightly, Heisig’s RTK system also teaches 空 with roof-and-legs despite introducing a named ‘hole’ component later – I don’t know if this is coincidence or if there’s a common underlying reason. These characters share the same traditional radical 穴 so it’s not an “inherited from the traditional radical scheme” difference.

Personally I think it’s just tricky to come up with a system for 2000 kanji that doesn’t have a few odd inconsistencies in it here and there. For RTK I think that sometimes for Heisig personally a mnemonic based on a slightly more split-up set of component choices happened to be more memorable for him than one based on the most “chunked together” possible component description, and so he chooses the more split-up analysis sometimes. (RTK is more clearly a personal project by Heisig, so there’s a bit of his own personal preferences in the mnemonics and images chosen, and it also tries to push the student more towards making their own choices and mnemonics and images anyway.)


Thinking about it some more I think I would be 100% fine with the current progression if there was just a small note when the hole radical is introduced saying something like “you’ve already seen this radical in the 空 kanji”. This way I wouldn’t have been confused and it would help connect the new radical to an already familiar kanji.


This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.