Riku Onda, born in 1964, is the professional name of Nanae Kumagai. She has been writing fiction since 1991 and has won the Yoshikawa Eiji Prize for New Writers, the Japan Booksellers' Award, the Mystery Writers of Japan Award for Best Novel for The Aosawa Murders, the Yamamoto Shūgorō Prize, and the Naoki Prize. Her work has been adapted for film and television.