In Japanese folklore, Tennin are a type of divine spiritual being found in the Buddhist tradition. One type of Tennin appear as extraordinarily beautiful women known as Tennyo. They live in the Buddhist heaven and are servants of the emperor of heaven and companions of the buddhas and bodhisattvas who live there. They entertain those in heaven with music, dancing and poetry. 

Tsukioka Yoshitoshi, 1882

Tennyo sometimes fly down to earth wearing feathered kimonos (hagoromo) and it is these gowns that allow them to fly. There are many tales in Japan of love stories between Tennyo and human men. Similarly to the western swan maiden or selkie legends, if the husband hides the feather kimono, the Tennyo will not be able to return home to heaven.

Unknown ukiyo-e artist, Edo period.

Inaki Nobuyuki

Tennyo, artist unknown (via Wikipedia)