I only found one thread regarding this from 14 years ago but they haven’t find the reason there.
Is there any logic behind learning kanji, e.g. 員 on level 12 and then learn radical, which is exactly the same in the level 34?
There are many examples like that.
Is it to “refresh” the memory or something? Or is it redundancy from previous version of WK, where kanji and radicals were in different levels?
I think the higher level radicals are sometimes introduced to simplify composition of more complex Kanji.
So 員 is made up of mouth, eyes and fins or whatever they are called now. But Kanji that use this “radical” can now be made up of only 員 instead, which simplifies the mnemonics.
Now there’s an argument to be made for why they don’t simply use the Kanji itself instead.
I can see 2 reasons for that:
If they introduce a radical, the rule holds that all Kanji are made up of radicals on WaniKani. Instead of some being made up of other Kanji and Radical mix.
It might be beneficial to give the radical a slightly different word association than what is ideal for the Kanji (I don’t have an example at the tip of my tongue, but hope you know what I mean).
If you ask me, I’d prefer for them to just use the Kanji. But it is what it is, and WaniKani instead decided to go with the Radical route.
I think it’s just a quirk of the system to maintain the strict radical → kanji → vocab progression. I don’t think it makes a lot of sense myself.
A particularly egregious instance is the below 下 radical currently introduced on level 59 which is just a copy of the ultra-common kanji you learn on level 1. By the time you reach level 59 you probably don’t need to review 下…
It does make sense though. Using the same example:
You learn 員 at some point as a kanji, using some other radicals in the normal way. So now you know that one. Turns out, there are some even more complicated kanji that have 員 in them.
So at that point we say, ok now let’s treat 員 as if it were a radical itself, so we can learn these more complicated ones. Otherwise we’re going to end up with big unwieldy radical lists and mnemonics. And it’s free, building on what you already know, nothing extra to learn.
This is why the order of the lessons in WaniKani is what it it. Later ones are built on the foundation of having learned previous ones. In the beginning, there’s no avoiding some amount of “see this arbitrary thing? Just memorize it” because you don’t already know anything. Better if you can shift as soon as possible to “you already know this, let’s use that to build with.”
Or is your question, “why do we have to do a whole lesson and reviews for the radical we already know from the kanji” → it’s probably easier than making a special case exception, being in the list of radicals makes them easier to look up, and the review only takes 3 seconds anyway.