I’ve read a few Japanese books by now, all of them were very enjoyable, so I want to write down some impressions here and for what level I’d recommend them. With text samples, so you can judge for yourself.
Kiki’s Delivery Service (魔女の宅急便) by Eiko Kadono
The first Japanese novel I read from start to finish. It was already covered in the book clubs, so I won’t get into too much detail. It is easy to read in terms of kanji usage, but beginners shouldn’t be fooled by that. You need to have a decent grasp of Japanese language in order to read this book with ease (and probably any longer book not strictly written for learning purposes). Grammar and vocabulary are not too advanced, but Kadono often uses language in a playful, non-straightforward way which might make it confusing if you still struggle with the words and grammar itself. I felt that the lack of kanji actually sometimes makes it harder to read. Also uses a LOT of onopatopoetic words that any non-Japanese person will probably not be too familiar with. Still, this is a good entry point and a good "tadoku" book. You will be able to make good progress if you don’t obsess over trying to understand everything. It’s also a wonderful series full of magic in the mundane, charming characters and you will be able to witness the growth of Kiki over a long span of time.
Read books 1-4 so far, all of them are more than worth their time.
Kemono no Souja (獣の奏者) by Nahoko Uehashi
The anime adaption is by favorite anime series ever, so I was naturally curious to read the source work, especially since the anime only adapts the first two volumes out of four + one "gaiden" book (side story). But it took me three attempts to make it through the book. It was actually the first Japanese book I tried to read, and I was overwhelmed at first with new vocabulary. Uehashi uses a very rich vocabulary, including many words you won’t hear in daily conversations, and the Asian-inspired medieval fantasy world does not make it easier. I had to look up 30+ words on the first page, and only managed to read up to page 100 in my first two attempts. I then discovered that it is MUCH easier to just read the eBook version, convert it to HTML and use one of the rikai addons to hover-lookup words. Saved me so much time.
After getting used to the vocabulary, I think intermediate / upper intermediate readers will have a lot of fun with these books. There will always be parts that feel a little overwhelming, especially when it gets political or delves deeper into biology, but the grammar and sentence structure itself is not too hard.
And it’s a such wonderful story, too. Lots of time dedicated to the development of the main character Erin and how she perceives the world. Entire chapters are about bee-keeping and how it helps Erin understand the world better until eventually her curiosity and love for animals lead her to develop a bond with a winged beast people are not supposed to get too close to. She then unwillingly gets dragged into a political conflict. Despite everything, it never gets too idealistic. It is always made clear that humans and those winged beasts, despite both being intelligent creatures, can never truly understand each other. Uehashi is excellent at describing fantastic, yet believable worlds. The fantasy elements are not too pronounced, there’s no magic and no superpowers. Everything feels organic and the setting is clearly Asian/Japanese as opposed to typical Western fantasy books. The lore is also very rich. But best of all, the reader gets to witness Erin’s development over 20+ years. I love these books so, so much.
But they are definitely NOT recommended for beginners. Too many uncommon words and use of role language for that. The bunko version has few furigana and usually only once for every word (with some advanced words without furigana entirely), so pick the Aoi Tori version if you want lots of furigana.
母は、闘蛇のなかでも、常に先陣を駆け、敵陣を食い破る役目を担う最強の闘蛇 --〈牙〉たちのお世話を任されている。友達のサジユの父や、チョクの父だって、 〈牙〉たちがいる岩房は任せてもらえない。闘蛇の世話役である闘蛇衆が、母の獣ノ 医術の腕をそれほどに高く買っているのだと思うと、エリンは誇らしさで胸がはちき れそうになる。
Tunnel no Mori 1945 (トンネルの森１９４５) by Eiko Kadono
Another book by the other of the above-mentioned Kiki novels. This, however, is a wartime novel, with strong autobiographical elements. It’s about a little girl, Iko (nickname for Eiko?), who moves from Tokyo to the rural outskirts to escape the regular bombings. It’s also about her relationship with her father, step-mother and kids at her new school. Everything is written through the eyes of a child and feels very authentic. Considering the theme, you might expect a full-blown tragedy like Grave of the Fireflies, but this is not the case. While the war always hovers over the story like a dark shadow, the essence of this book is very mundane and not very dramatic, although sad things definitely do happen. Very recommended in any case. Also has some beautiful illustrations.
As for the language, it’s a bit more advanced than Kiki and has some historic vocabulary, but definitely not too hard. I’d recommend it to lower intermediate readers and upwards, or beginners who want to challenge themselves.
The comparatively low page count also makes it a good entry point for someone who doesn’t want to get overwhelmed by an epic like Kemono no Souja.
Shizuka na Hibi (しずかな日々) by Michiko Yazuki
This book is very nostalgic and mundane. It’s about a boy in 5th/6th grade who lives alone with his single mother but moves to the rural home of his grandfather during the course of the story. He is very shy and never had any friends, but finally starts to get more socially involved when he meets another more outgoing boy. They become good friends and have a couple of adventures during their summer holidays. The book also depicts the difficult relationship he has with his mother, and the intimate relationship he develops with his grandfather who initially makes a cold impression. Very mundane story, but it hits all the right spot, is written in a very introspective way, and both children and adults are very well-written and believable.
The language and grammar are relatively simple, but it uses more advanced vocabulary and kanji than books I’d recommend for beginners. I think Shizuka na Hibi is a good read for intermediate readers.
Konbini Ningen (コンビニ人間) by Sayaka Murata
Out of this list, this is the only book aimed at adults first and foremost. Considering that, it is not too difficult. The book is written in a very straightforward way, partly owed to the protagonist who has autistic traits and tackles everything in a very pragmatic manner. Obviously uses vocabulary you wouldn’t find in children’s books, but it’s definitely a long shot from more poetic literary works.
As for the content, it’s about a 37 year-old (iirc) woman who cannot and does not want to fit in and is basically happy with her work in a Convenience Store, and a young mysogynist man who always curses the society, but in truth desperately wants to fit in. The book was eye-opening for many people in Japan because it shows that not everyone can lead a life according to the expectations of the society.
It’s also pretty short.
I’d recommend it for intermediate or upper intermediate readers. Nothing too difficult, but it might get exhausting if you don’t have a solid foundation to build upon. The book is also not split into chapters which means there are no convenient places to stop reading.