I also asked this some time ago. I’ll take みなみsan’s answer. It seems to be the difference between permitted form for older pc, and the official form for nowadays pc; with the death mask one being the official one. (but you can’t link it or interact with it.)
Using Sans font will be ‘former’ radical, and Serif will be death mask.
It took me like two months to realise that 入場 and 入所 are actually two different words (with the same meaning).
外れる
Level 3
Unlocked August 26th, 2015
Just missed the burn, again…
ひめ ー 姫 ー princess
ひめ ー 媛 ー princess
ひ (!) ー 妃 ー princess
≠ princess
The seven different words for anticipate/expect are going to be floating between guru and enlightened forever for me, I think.
YES! Oh god yes I hear you with those!! Haha
I got curious about what my leeches were and I realized there’s no easy way to just simply display them, so I wrote a small script that queries the API for my kanji and vocab, and then applies this simple formula to determine which are leeches:
total number of incorrect responses / current correct streak
So here’s what I got and my thoughts about each of them:
Item Type Item Card Type SRS Score
1. vocab 作業 meaning 5 12.0
2. vocab 取れる meaning 5 8.0
3. vocab 資料 meaning 4 8.0
4. vocab 除く reading 2 8.0
5. vocab 資格 meaning 5 7.0
6. vocab 想定 meaning 6 6.7
7. vocab 取決め meaning 5 6.0
8. vocab 苦労 meaning 5 6.0
9. vocab 嫌味 reading 5 6.0
10. vocab 整然 meaning 3 6.0
So every one of them is a vocab, the first Kanji isn’t until 14 (the meaning of 安). Looking at the list kinda sends a cold sweat down my back as every one of them has been painful for me, so I think the algorithm works. One by one:
作業 Meaning
Work
Provided mnemonic
If you want to make a business successful you need to be prepared to do a lot of work.
What’s going wrong?
I keep getting it mixed up with 作家, and the mnemonic kind of turns on a pun of the word “make” that’s not sticking. It’s also just super old for me and keeps falling out of streak around Enlightened.
Remedy
Nothing specific, I think I just need to pay better attention for this one considering how many times I’ve screwed it up.
取れる Meaning
To Come Off
Provided mnemonic
This is like 取る, which is “to take.” Now though, instead of you doing the taking, it’s just “taking itself” so to speak. That doesn’t make sense, though. When something its taken by itself, it is something that just comes off. So, you can call this to come off. You can remember that this is “to come off” instead of “to take” because it is rare (れる) that something comes off on its own without your help.
What’s going wrong?
It’s linguistically bizarre to me that the intransitive form of “to take” is “to fall off”. My brain just rebels.
Remedy
I think I just need to see this word used in context more often, it seems like such a common and easy word.
資料 Meaning
Material
Provided mnemonic
The material you use to make resources is still material.
What’s going wrong?
Meaning relies on secondary definition of 料 that I never committed to memory. I also don’t have a strong grasp on the sense of the word “material” we’re talking about here, as “material” in English has a fair few meanings.
Remedy
Maybe a new mnemonic that relies on the “fee” meaning? Suggestions? This one confounds me.
除く Reading
のぞく
Provided mnemonic
You would like to exclude your nose (のぞ) because you don’t like your nose. Imagine your strong feelings about your nose as you decide to exclude it.
What’s going wrong?
It’s a very new kanji to me. I am getting severely lost in the plethora of 余 kanji, and the 送り仮名 provided gives me basically nothing to latch on to. Plus, 訓読み are always a little tougher.
Remedy
I think here I can just double-down on the provided mnemonic and make it stick. It’s slightly weird, but it is nowhere near one of the really bad ones.
資格 Meaning
Qualifications
Provided mnemonic
The credible resources that determine your professional status are your qualifications. You need some good ones if you want to get into a good school or land a sweet job.
What’s going wrong?
What is even with this mnemonic? Resource + status without any particular hooky story around it is pretty useless. Throwing the word “credible” in there isn’t helping, as it has nothing to do with anything. Both “resource” and “status” are very general words in English that have a variety of meanings, so I partially blame this on my poor grasp on the constituent kanji.
Remedy
Need a new mnemonic badly. Hmm… maybe something on my resume about how I paradigm-shifting, industry-leading, effective-communicating in my job managing different resources and their statuses? Seems pretty dubious… help?
想定 Meaning
Hypothesis
Provided mnemonic
You’re trying to determine the concept behind something but you have to test your hypothesis first. You have your assumptions, but you’re not entirely sure you’re right yet because all you have is the concept to go off of.
What’s going wrong?
Again “determine” and “concept” are fairly vague words. The provided mnemonic is a little word-soup-ish.
Remedy
Needs a new mnemonic. No ideas yet.
取決め Meaning
Arrangement
Provided mnemonic
You’ve taken a decision from someone. By doing this, you’ve created a kind of arrangement with them. Imagine yourself pulling this decision out of the person. They don’t want to necessarily give it to you, but they’re letting you pull it out of them, kind of. When you’ve pulled it out, you’ve come to an arrangement, though they’ve pulled some of your decision out too.
What’s going wrong?
This is a really strange word all on its own. I don’t well understand the sense of “arrangement” intended here. Strange mnemonic, but I don’t think they had that much to go on with such a strange word.
Remedy
I think I just need to see this one in context a bunch more.
苦労 Meaning
Hardship
Provided mnemonic
Suffering and labor. Sounds like the kind of thing these soft hands wouldn’t want to deal with. These are hardships and troubles. Hopefully you don’t have too much of this with kanji anymore!
What’s going wrong?
I’m a little surprised to see this one so high up as it doesn’t feel to bad to me. Nothing all that wrong or unintuitive about the mnemonic, either.
Remedy
Just seeing it on the list might be enough. I’ll give this one some time to sort itself out.
嫌味 Reading
いやみ
Provided mnemonic
The reading for 味 is the on’yomi you learned with the kanji, but the reading for 嫌 is the kun’yomi, いや. Just imagine someone saying words so hurtful that you have to scream, “Iyaaaaa!” いや.
What’s going wrong?
I keep getting this one mixed up with 嫌悪. It’s a bit odd having 音読み and 訓読み in the same word. I think the mnemonic works fine, though.
Remedy
Probably just practice practice.
整然 Meaning
Orderly
Provided mnemonic
When you arrange things in the way that nature intended, you’re doing things in a quite orderly fashion. This is the natural state of things, nice and arranged and natural. Orderly!
What’s going wrong?
Getting 然, 熱 and 烈 mixed up a bunch probably isn’t helping. Nothing wrong with the mnemonic I don’t think.
Alright, that’s too much already. Let’s squash some leeches! 
Could you share that script? It sounds super useful!
For 想定 I can refer you to this post.
Sure. Here it is: Leech Detector.
It’s a bit jank, but I just spent an hour or so cleaning it up so hopefully others find it useful. Be patient with it, after the kanji loads it takes a while longer to bring in the vocab. Let me know if you want it to do anything else.
thanks…oi…yeah that’s exactly all the items that are keeping my apprentice at 100 lol…ugh. useful though to see it in list form. some are due to me and my bad typing too fast and hitting enter like a doofus. I also still have trouble with transitive vs. intranstitive forms of verbs (to decide vs to be decided/settled…often forgetting which is which).
The highest score on mine is 5.0 with the top ten as low as 3.0. But I definitely have some leeches, so…
You think the algorithm is wrong? Any suggestions?
What are the ones you’d consider leeches, and what are their scores on that page?
These probably aren’t my worst, but scanning through the list here are three I consider leeches:
折角 - 1.7
行動 - 4.0
友好 - 2.0
To be fair, these are all in the top 25 of my list. The numbers just feel small compared to the numbers @StellaTerra gave.
Well, Stella also described the formula. So that just means your worst words aren’t as bad as Stella’s. Congrats.
Hmm… alright. Yeah, my intention was to capture a moment so that I could revisit it 2-3 times a month, so the division by the current streak is probably what’s bringing those guys down. You may be looking for something even simpler, like just total number of wrong answers. Does that sound more on course for you?
Yeah, it’s probably just that my leeches happen to be in Guru/Master at the moment. I’m sure they’ll drop back to Apprentice soon enough… I’d be curious to see just total number of wrong answers. Did that formula not give you a satisfactory list? Or were you just more focused on leeches with a lower SRS score as more immediate problems?
The leech detector supplies the SRS level, don’t know if you saw that, but for my top 10, I had 3 in apprentice, 7 in guru, my worst master is #40 (利く meaning), and my worst enlightened was #22 (交じる meaning). I guess I figured if you got a word/kanji wrong 5-10 times while it was in apprentice, but you’ve got the last 3 right, it’s probably a dead leech, so 10 / 3 = 3.3, which sounds about right. But if you got it right all the way to enlightened, and then missed the burn, and then missed the next two, you’re at about the same level of concern. At least for me, leeches tend to revive themselves so correct answers diminish concern, at new wrongs elevate it.
Did that formula not give you a satisfactory list?
I’m a little confused about that, I’m satisfied with the results for myself.
Or were you just more focused on leeches with a lower SRS score as more immediate problems?
The algorithm ignores SRS level. I don’t see how this is an alternative to being dissatisfied with the list. I think I’m missing your question here. Like I said, I’ve got an enlightened at #22, and boy howdy have I got that sucker wrong a lot of times. 
I don’t know though, I guess I’m asking, could you restate your question?
Wait, are you suggesting simply dividing the number of wrong answers by the number of right ones, like globally? That might be worthwhile, but it would make older, dead leeches show up more prominently, and take longer for leeches to show up.
My confusingly-worded question was really just asking if you ever tried the straight “total number of wrong answers” approach and if you were satisfied with what you found (stupid question since, if you did try it, you obviously weren’t satisfied since you came up with a different formula).
Current streak (for the worse of meaning/reading) is effectively the SRS level, which is why I mentioned that.
I think I’ll just have to check for results again in a few weeks to see if some of my leeches become more prominent.