Hey, my teacher said N2 is really about "knowing synonyms", ex. the text will say "elders" but in the answers you can pick from it'll say "old people" and you have to know they mean the same thing.

Meanwhile N1 is supposedly more about knowing "why" someone said something or "why" something occurs, ex. "why" does the fish not chase after its prey - so N1 might actually say the same thing a couple different ways because it doesn't care if you don't know synonyms or not.

Hey, sorry I haven't been around to make this comm active, I've been... busy... livin' life in Japan... yeah. If you have questions or want me to look for books for you or something just let me know. I can get stuff like picture books, magazines, manga etc for super cheap (100-300 yen each) at the used bookstore if you want anything. Ex. I just bought the entire Evangelion manga series for 400 yen.

Anyway I'm gonna take the JLPT N1 this July. I'm taking 2-3 classes at uni specifically aimed at getting students to pass N1 (and N2), and as far as I know the textbooks are:
• アカデミック・ジャパニーズ
• 日本語能力試験 20日で合格 N1文字・語彙・文法本
• 日本語能力試験問題集N1文法スピードマスター

I also just found a new N1 grammar point I don't remember seeing before, which you can see here on this page (I don't trust these pages too much but it's all I have right now):

http://japanesetest4you.com/flashcard/learn-jlpt-n1-grammar-%E3%81%A8%E3%81%BF%E3%82%89%E3%82%8C%E3%82%8B-to-mirareru/

I saw it in a tweet from Miyagi County News about the olympics, which I'll copy here with spaces for you learners:

「オリンピック 2 連覇 を 達成 した 羽生 (Hanyu) 結弦 (Yuzuru) 選手 の 祝賀 パレード に 向け 事前 予約 が 始まって いる 記念 グッズ が、オークション サイト に 多数 出品 されて います。転売 目的 と みられ、実行 委員 会 は 正規 の 方法 で の 購入 を 呼び 掛けて います。」

Here I'll link to / list things that I consider to be N1 level as I find them, since everyone needs reading practice but even at N1 we're still not at "native level" yet. N1 is essentially made up of archaic grammar, irregular or rare kanji usage, jargon, and extremely poetic stuff/flowery writing.

Stories:
• 愛よ愛 by 岡本かの子: http://www.aozora.gr.jp/cards/000076/files/4554_15427.html

Fanfics:
• (Kabaneri) https://www.pixiv.net/novel/show.php?id=7666616

Watching:
• 沖縄と核 (Documentary on America keeping atomic missiles/bombs in Okinawa): https://www.youtube.com/watch?v=vFkBWgsDuow