Reddit reviews I Am a Cat (Tuttle Classics)

I don't really read enough mystery/thriller to give recommendations, but here are some Japanese "normal" books I recommend (all Amazon links):

Night on the Galactic Railroad
ICO: Castle in the Mist
The Book of Heroes
I Am a Cat
Silence
The Samurai
Kokoro

Soseki Natsume - I am a Cat

Considered a Japanese classic.

Similar has been already in the Japanese literature a century ago.

http://www.amazon.com/Am-Cat-Three-Volumes-One/dp/080483265X/ref=sr_1_1?ie=UTF8&qid=1413955311&sr=8-1&keywords=I+am+a+cat

http://en.wikipedia.org/wiki/I_Am_a_Cat

Or, a novel. It would be like I Am a Cat but more action packed...

I Am A Cat by Soseki Natsume. It's a story from a cat's perspective about life in Japan in the 20th century.

Manga seems an obvious choice here, something like Yotsuba to could be fun. Others to check out are Kamikaze Girls and Nana

In terms of mythology and folk lore:

Lafcaido Hearn's ghost stories are quite fun.

As is this book on Japanese monsters - The Book of Yokai

Lastly, I am a literature person so I have to recommend at least one piece of literature. Perhaps something like Banana Yoshimoto's Kitchen or Soseki's I Am a Cat could be good a young reader and serve as an introduction to Japanese literature. Though admittedly the Soseki may a little much for 12 years old. It is a great book though!