株式会社タイムカプセル社 十年前からやってきた使者 新版 喜多川泰シリーズ

This was the first novel I read in full in Japanese, even though I'd already passed the N1 and was conversationally fluent. There were still some words I didn't know since I didn't have much experience with novels, but a lot of those words I learned went on to appear in the second novel I read (and elsewhere), so they're all very useful. I feel like this book helped me fill in a lot of the blind spots I had in my knowledge.

Some characters speak with a dialect, but it's easy enough to understand. Since they go all around Japan in this book, I learned a few place names as well, like 苫小牧。

The premise is really fun and engaging and it's a novel I wish I could recommend to even my English-speaking friends. Definitely worth a read!