question: What Japanese anime series is inspired by a fairy tale written by Hans Christian Andersen?
answer: Princess Tutu
context: Title: The Nightingale (fairy tale)
  Passage: "The Nightingale" (Danish: "Nattergalen") is a literary fairy tale written by Danish author Hans Christian Andersen about an emperor who prefers the tinkling of a bejeweled mechanical bird to the song of a real nightingale.  When the Emperor is near death, the nightingale's song restores his health.  Well received upon its publication in Copenhagen in 1843 in "New Fairy Tales", the tale is believed to have been inspired by the author's unrequited love for opera singer Jenny Lind, the "Swedish nightingale".  The story has been adapted to opera, ballet, musical play, television drama and animated film.
  Title: The Ugly Duckling
  Passage: "The Ugly Duckling" (Danish: "Den grimme ælling") is a literary fairy tale by Danish poet and author Hans Christian Andersen (1805–1875).  The story tells of a homely little bird born in a barnyard who suffers abuse from the others around him until, much to his delight (and to the surprise of others), he matures into a beautiful swan, the most beautiful bird of all.  The story is beloved around the world as a tale about personal transformation for the better.  “The Ugly Duckling” was first published 11 November 1843, with three other tales by Andersen in Copenhagen, Denmark to great critical acclaim.  The tale has been adapted to various media including opera, musical, and animated film.  The tale is completely Andersen's invention and owes no debt to fairy tales or folklore.
  Title: Princess Tutu
  Passage: Princess Tutu (Japanese: プリンセスチュチュ , Hepburn: Purinsesu Chuchu ) is a Japanese magical girl anime series created by Ikuko Itoh in 2002 for animation studio Hal Film Maker.  Inspired by ballet and fairy tales, particularly "The Ugly Duckling" and "Swan Lake", the story follows a duck who is transformed into the mythical ballerina Princess Tutu in order to save the shattered heart of a storybook prince come to life.
  Title: Andersen Monogatari (TV series)
  Passage: Hans Christian Andersen Stories (アンデルセン物語 , Anderusen Monogatari ) is a Japanese anime series by Mushi Productions and aired on Fuji TV from January 3 to December 26, 1971.  It's about the legendary stories of Hans Christian Andersen.
citations: Princess Tutu The Ugly Duckling