World Masterpiece Theater
"Heidi" is one of several World Masterpiece Theater titles produced around the "classical children's literature period" (1974–1997), based on classic tales from the Western world. The animation studio responsible for Heidi, Zuiyo Enterprises, would split in 1975 into Nippon Animation Company, Ltd. (which employed the anime's production staff and continued with the World Masterpiece Theater franchise) and Zuiyo Company, Ltd., which retained the rights (and debt) to the "Heidi" TV series. The feature-length film edit of the TV series, released in March 1979, was engineered completely by Zuiyo, with no additional involvement from Nippon Animation, Takahata or Miyazaki.