A Tale for the Time Being by Ruth Ozeki

Nao lives in Tokyo. She is sixteen, and has decided to write a diary before she kills herself. She has plenty of material - school bullies, depressed parents - but she particularly wants to chronicle the life of her great-grandmother, Jiko, a Buddhist nun. And eventually, Nao thinks, her diary will find its reader.

Ruth lives with her husband on the Pacific coast of Canada. A few months after the 2010 tsunami she finds a Hello Kitty lunchbox washed up on the shore. It contains a diary...