In Japanese Buddhist belief, the bosatsu (future Buddha) is considered the god or goddess of mercy. Kannon was originally a male god but eventually came to be considered female. Myths and legends therefore sometimes portray Kannon as male, sometimes as female. According to myth, Kannon was born when a beam of light flashed from the right side of the Buddha Amitabha. She decided to stay on earth as a bodhisattva, or “Buddha-to-be,” and help humankind.
Jeremy Roberts, Japanese Mythology A to Z, 2nd Ed., Chelsea House