The gender-bending main character was inspired by the all-female musical theater group Takarazuka Revue in which women performed both female and male roles.

The manga's popularity resulted into a radio dramatization in 1955, three other serializations between 1958 and 1968, and a 52-episode television anime series by Mushi Production that aired on Fuji TV from 1967 to 1968.

The manga would only reach the anglophone public years later, in 2001 when Kodansha International published a bilingual edition of Princess Knight, which was followed by a newer version by Vertical in 2011.

Taking place in a medieval European-like fairy tale setting, Princess Knight is the story of Sapphire, who must pretend to be a male prince, so she can inherit the throne of Silverland as women are not eligible to do so.

Sapphire also dons a Zorro-style mask at night, fighting crime as the Phantom Knight, and gets involved with Franz Charming, the young prince of neighboring Goldland.

Tink has been mortally wounded by the castle's breakdown, and tells God that he is ready to sacrifice his life should Sapphire's parents be brought back from the dead.

[18] Born in Osaka, Tezuka lived in Takarazuka City between five and twenty-four, and with a mother who was fan of the revue, he often watched its performances during his childhood and youthhood.

[1] Some aspects of Princess Knight are also reminiscent of his previous shōjo manga, Kiseki no Mori no Monogatari, which featured a feathered hat and men in white maillots as well as adventure-driven storylines.

[26] Reviewers have perceived influences from Cinderella,[8][24] Fantasia's "Pastoral",[24][25] Pinocchio,[24] Sleeping Beauty,[7][8] Snow White,[7][24] Betty Boop,[7] Captain Blood,[24] Dracula, "Eros and Psyche",[25] Hamlet,[24][25] "The Sorcerer's Apprentice",[27] Swan Lake,[24][28] The Scarlet Pimpernel,[26] and William Tell.

Patrick Drazen, author of the book Anime Explosion!, stated the androgyny in the series is "deceptive" as it addresses gender instead of sex, and more "specifically, gender-role expectations.

[30] Ed Sizemore of Manga Worth Reading says Tezuka's central idea critiques "the false dichotomy that society creates among male and female.

On the other hand, Silverman affirmed it shows gender stereotypes and "some of the more misogynist ideals of 1960s Japan," as exemplified by the fact her boy's heart gives her physical strength.

"[32] For Paul Gravett, it demonstrated she "was no feminist rebel after all" and he wrote in Manga: Sixty Years of Japanese Comics that Tezuka "created an exquisite world of indecision.

[h] Snow Wildsmith of ICv2 described the series as having "younger characters [who] do not want to stick to the roles their parents proscribed for them and most of the women are tired of being told that they are the lesser sex.

[54] The third serialization was a rewriting of the Shōjo Club version and ran from January 1963 to October 1966 in Nakayoshi,[55] and was originally published into five tankōbon volumes by Kodansha[56] between August 15, 1964 and June 15, 1966.

[83] Mushi Production submitted the anime adaptation to NBC Enterprises that was declined because its executives felt the series theme could be interpreted as "sex switch.

[87] One of the author's most popular works in Japan,[8][71] it has been labeled as "a fascinating piece of anime history ... that's withstood the test of time" by Bamboo Dong of ANN.

[103] After Vertical's statement that it would publish Princess Knight, critics Chris Butcher and Deb Aoki deemed it as one of the most anticipated manga announced at Comic-Con.

[14] Aoki, for About.com, selected it as the second best new shōjo released in 2011 after Sailor Moon, stating it "can seem a little dated and quaint compared to its contemporary counterparts, but it's no less charming and fun to read.

[105] Its art has been well received by critics, including Sizemore,[24] Joseph Luster of Otaku USA,[13] Wildsmith,[35] Chris Kirby of The Fandom Post,[28] and by Mautner, who stated, "Visually, Knight is a stunning achievement.

"[28] Sizemore praised it as it "constantly delivering thrills at each turn,"[24] contrasting to Wildsmith, who considered the episodic nature of the series "chaotic and unfocused".

"[106] Shaun A. Noordin of The Star asserted, "The memorable characters, adventure, drama and comedy (not to mention a framework for exploring issues such as feminism, gender equality and identity) are all there, but the barrage of story arcs made it difficult for us to be invested in the narrative.

[2][108] It also established elements that would be common in late works of the genre, including an idealized foreign (from a Japanese perspective) settings, a heroine with large eyes, and gender ambiguity with a certain amount of androgyny.

[2][29][109] In the 1970s, two trends were predominant in shōjo manga: the first featured "androgynous, masculine, or asexual protagonists searching for self and love" and the other had "more explicit romance involving an ordinary girl."

[3] Martin Theron of ANN affirmed the series' "influence ... is immeasurable, and in a real sense every lead action heroine who has followed is a direct or indirect spiritual descendant of Princess Sapphire/Prince Knight.

[113] This work expanded the scope of Japanese popular culture by opening up the possibility of exploring a wider range of sexual orientations, which goes beyond clear gender binary homo- or heterosexuality.

[36] According to Brophy, "Shōjo manga's rich potential for complex representations of the human psyche in diverse sociocultural contexts was essentially constructed by Tezuka's androgynous character Sapphire.

[120][121] To commemorate the 60th anniversary of the series, a reboot version of Princess Knight started to be published on the online manga magazine Puratto Home by Home-sha in July 2013.

[130] Another musical came in 1998; it was directed by Shunsaku Kawake, written by Kensuke Yokouchi, and starred Yoshihiko Inohara, Sae Isshiki and Ranran Suzuki.

[141][142] It starred Nogizaka46's Erika Ikuta and Reika Sakurai as Sapphire and Hecate respectively, while Keisuke Kaminaga and Tsunenori Aoki completed the main four in the poster, playing Prince Franz and the pirate Blood respectively.