Hi there. I don’t try to post nitpicky feedback very often, as by and large I love the way the site is set up. Just had to ask why 到 is placed at such a high level (42; just checked), and wondered if it might be moved down into the early 20s in the future.
As it stands, it’s one of the few JLPT N3 kanji hanging out at a level ridiculously higher than the rest, its radicals are all taught by the early 20s, and it’s a fairly common kanji that’s even used in antonyms to some of the site’s earliest vocabulary. (Ex., the 到着 to the early 出発; even 着 shows up early on.)
It seems more sensible on the grounds of related kanji, complexity, usefulness in daily life (even for tourists; those time tables), and test-prep to move this one a bit further down. Unless there’s a good reason. And I don’t know; maybe there is. If not, just food for thought for whenever a big update happens in the future.
到頭, albeit usually written in kana, also shows up around that level of study and uses two common kanji.
I suppose “not that much vocab” could be a viable reason. 到達 and 到底 are also constructed with kanji introduced at lower levels, though they’re much less frequently used and I suspect are kind of high-register.
I did just flip through my N3 book though, and it isn’t there, so maybe it’s not so urgent. Just got a bit spooked by seeing it listed there on jisho.org (which I know isn’t super reliable), and between how simple the kanji is and how useful 到着 is, I was having trouble imagining why it was placed so high up. (Especially if it was a rogue N3 omission, but maybe it’s not.)
Lack of vocab, a G9 designation, and not actually being a regular part of the N3 would all be good reasons though. In which case, question answered, I guess.
I hope lack of vocab isn’t an excuse for sticking something at a high level, since I could make a considerable list of kanji from my level down that only have two vocabulary (and/or one at a level nearby), including the level 2 刀.
From quick examining, along with @acm2010’s finding that it is a G9 kanji, I think the WaniKani reason is the use of the 音読み for 着. ちゃく isn’t used on any lower level words containing 着, with the first word containing it at 37 with 執着. Afterward, there’s an instance of it within 5 levels all the way to 55. Similar to 合’s reading of ごう, I think the idea was to transition it in steadily so that it would more easily stick.
Dang, that’s probably it. I’m so used to that reading from the clothing counter 着, 到着, and 着席 that it didn’t even occur to me it was one WK held off on.
