From the Kabuki play "Ashiya Michimitsu Ouchikan".
A white fox whose life is saved by "Abe no Yasuna" disguises herself as "Princess Kuzunoha" and becomes Yasuna's wife, giving birth to a boy. When the child turned seven years old, Princess Kuzunoha was discovered to be a fox, wrote a farewell poem on a shoji for the child, and returned to "Shinta no Mori" with tears in her eyes. The child grew up and became a genius yin-yang master (a person who divines as a national occupation) named "Abe no Seimei".