Akira also tells me this:
It is related in the seventh volume of the book Kamakurashi that there
was formerly at Kamakura a temple called Emmei-ji, in which there was
enshrined a famous statue of Jizo, called Hadaka-Jizo, or Naked Jizo.
The statue was indeed naked, but clothes were put upon it; and it stood
upright with its feet upon a chessboard. Now, when pilgrims came to the
temple and paid a certain fee, the priest of the temple would remove the
clothes of the statue; and then all could see that, though the face was
the face of Jizo, the body was the body of a woman.
Now this was the origin of the famous image of Hadaka-Jizo standing upon
the chessboard. On one occasion the great prince Taira-no-Tokyori was
playing chess with his wife in the presence of many guests. And he made
her agree, after they had played several games, that whosoever should
lose the next game would have to stand naked on the chessboard. And in
the next game they played his wife lost. And she prayed to Jizo to save
her from the shame of appearing naked. And Jizo came in answer to her
prayer and stood upon the chessboard, and disrobed himself, and changed
his body suddenly into the body of a woman.