Her first novel, When the Emperor Was Divine (Knopf, 2002), is about the incarceration of a Japanese-American family during World War II. It has been translated into eleven languages and was a New York Times Notable Book.
The book is based on Otsuka’s own family history: her grandfather was arrested by the FBI as a suspected spy for Japan the day after Pearl Harbor was bombed, and her mother, uncle and grandmother spent three years in a prison camp in Topaz, Utah.