Honestly, N1 grammar is rare. That’s just a fact. It’s the least common sort of structure you’ll run into in any coherent text, so you won’t see it much. However, you’ll definitely come across it here and there in various places. I don’t read all that much, so I’ll leave you to take others’ suggestions with regard to fiction that you might be able to encounter such structures in.
If you want to take the quick route though… just get the Shin Kanzen Master N1 Grammar book and go through all of it. It might not be as fun as reading to learn grammar, but at least you’ll have everything. (Case in point: I got 51/60 for language knowledge despite getting almost zero for N1-specific grammar on my first practice test, and I only had a month to study for the N1, most of which I spent on SKM N1 Grammar. Mind you, I didn’t even finish the book because I didn’t have the time. I stopped at lesson 12 or 13.) You might forget everything you’ve studied after the test – we each have different levels of retention depending on how we studied something – but at least you probably won’t struggle with the grammar used on the N1. Still, to be fair, the N1 doesn’t actually test all the grammar listed in books like the SKM one: around 75% of the grammar questions referred to structures that were much more common, perhaps so-called ‘N2 level’ structures, and only a small handful of them were keigo-specific or somewhat archaic N1-specific Japanese. You don’t actually need to know everything to do well. It’s just that N1 grammar can also appear in some of the other sections (especially reading and listening), which means you need to know them in order to understand the material.
Even if N1 grammar therefore isn’t ‘that hard’ (as compared to the expectation SKM might give you), what I will say though, is this:
This is effectively the sort of stuff that comes up on the JLPT. Almost all of the passages feel like news articles or editorials, with a few of them being reflective essays. The main reasons I’d recommend reading these if your goal is test prep are
- You can get used to the writing style of length of these passages.
- You can see what sort of vocabulary is used on the test.
It’s true that all specialised vocabulary and rare expressions on the test are explained in footnotes, but going through a passage where there are tons of words whose meaning you’re only half-certain about isn’t that fun or easy, especially if you’re tired. I mean, there’s more than half a year to the first JLPT session next year, so you’ve got plenty of time to build up a reading habit, but if you don’t have much time for test prep or Japanese in general, I think you’d be better served focusing on reading non-fiction and the news if you want the best chance at knowing all the words that appear on the test.
I mean, I trust Vanilla on his recommendations, and I definitely haven’t read as much as him, so go ahead if those books interest you and you have the time for them, but as someone whose Japanese knowledge is mostly from anime + the occasional business Japanese site/university study, I was really frustrated by the sheer amount of newspaper-y vocabulary I didn’t know on the N1. I just didn’t know enough technical/formal words. To be clear, the issue wasn’t the vocabulary section – again, 51/60 for language knowledge, albeit mostly through reasoning by analogy and guessing using kanji – but rather the fact that I slowed down a lot during reading simply because the words I was seeing were so unfamiliar. All the fantasy, mecha, keigo and traditional Japanese grammar terms I knew were basically useless because that’s just not what the N1 tests. To put it another way, in my opinion and based on my experience, N1 grammar is not the biggest hurdle on the test, even if it’s true that it can be hard for some people and my grammar knowledge definitely carried me past the passing mark. Vocabulary is a way bigger issue simply because the words that appear on the N1 don’t turn up much in the Japanese media that most of us enjoy. It’s not ‘formal’ in the ‘polite’ sense (and I’m speaking as someone who enjoys learning stiff-as-f**k, convoluted keigo because I think it sounds elegant), but rather in how it’s very ‘proper’ and precise. Such expressions are much rarer in fiction, and so you typically won’t be ready just consuming fiction unless it’s fairly complex writing.
Ultimately, I’m not against people reading what they enjoy to learn more advanced Japanese, but since I went into the N1 without really knowing what the texts and recordings were like and really regretted it (even though I passed), I figured I’d offer what I wish I had done back then.