Futari no Iida/Two Little Girls Called Iida by Miyoko Matsutani.
If you ever find yourself in Japan, and enjoyed the movie Hotaru no Haka/Grave of the Fireflies, try to find this book. Don't worry, this is the English translation.
It is kind of a fairy tale, but it is extremely sad. It's about a little girl named Iida who finds a small chair. This chair is from the time before the bombs were dropped on Hiroshima, and it talks, looking for another little girl, its owner.