* AdaptationDisplacement: The 1966 version is much better known than original 1953 version and reprinted much more often. This makes it a rare example where the displacement comes from a SelfRemake.
* EndingFatigue: Generally agreed to be the main problem with the 1966 version. [[spoiler:Three-quarters of the way in, Sapphire has gotten her kingdom back, fixed most of the conflicts, and both of the {{Big Bad}}s are dead. One would assume the story ends there, but rather, Venus, [[DiabolusExNihilo a character never as much as alluded to]], shows up, kidnaps Franz, and starts a completely different plot about Sapphire and Franz trying to be reunited in a completely different setting. That Venus never actually interacts with Sapphire and the only other antagonist to be faced is [[IneffectualSympatheticVillain Sir Nylon]] doesn't help.]]
* FairForItsDay: While it can come across as sexist by modern standards (among other things, having it that [[WomenAreDelicate women are naturally timid, unsuited for fighting, and enamored of pretty things like dresses]]), Sapphire is TheHero who [[EarnYourHappyEnding fights for her happy ending]] and [[PluckyGirl becomes strong and brave enough]] [[ActionGirl to defend herself]]. Furthermore, while the series shows women as naturally being frail, it also showed that they ''can'' [[CharacterDevelopment grow to]] [[TookALevelInBadass be strong]] and most of the women were shown as [[WomenAreWiser being naturally brave, compassionate, and intelligent]]. Friebe and Hecate are shown as being good people while ignoring gender norms and engaging in unladylike behavior (and are shown to be very good at it). [[AristocratsAreEvil Duke Duralmin]] takes advantage of the kingdom's sexist laws to make Plastic, the only available male heir, his PuppetKing, while the heroes agree that the rules limiting the rights of women are outdated. [[spoiler:In the 1966 manga, when the women of the kingdom finally revolt, while the whole thing is generally PlayedForLaughs, they do put up enough of a fight to worry the Duke. Plastic granting women equal rights to men and letting Sapphire rule is shown as his being a true man and doing the right thing.]]
* GenreTurningPoint: This is one of the first narrative-driven Shojo manga and has massive influence in the entire genre, with notable examples include an androgynous lead heroine.
* SugarWiki/HeartwarmingMoments: In ''Twin Knights'', after [[spoiler:Franz, Sapphire, and Violetta have been locked in the tower by usurpers and Franz has been separated from his family, Violetta breaks down crying over what's happened. Sapphire calms her down, telling her, "You can't give in to bad people, even if things are tough".]] She then gets a sword off the wall and proceeds to train her daughter to improve her fencing.
* HilariousInHindsight:
** Can be either this or HarsherInHindsight. Whichever this manga exemplifies is up to you, but the possibility of a man's soul being within a woman's body and vice versa brings many current issues involving the LGBT community to mind.
** The title becomes this now following Princess Peach's Swordfighter outfit in ''VideoGame/PrincessPeachShowtime''.
* NarmCharm: The old-fashioned 50s and 60s dialogue, reveling in melodrama or exaggerating the words.
* OlderThanTheyThink: Sapphire having both a boy's heart and a girl's heart is reminiscent of [[http://en.wikipedia.org/wiki/Two-Spirit Two-Spirit people]].
* TransAudienceInterpretation: Sapphire is interpreted by some modern audiences as transgender, due to having a boy's heart in a girl's body.
* UnintentionallyUnsympathetic: Franz comes off as a selfish jerk to a lot of modern readers, who is more interested in a girl he knows virtually nothing about than actually ruling his kingdom.
* ValuesDissonance: The series operates under the idea that men and women are naturally inclined to act in certain ways. Princess Sapphire can do "manly" things (swordfight, adventure, etc) because she has both male and female hearts. If her male heart is removed, she instantly becomes timid and prone to swooning until she TakesALevelInBadass [[note]]It should be noted that Creator/OsamuTezuka apparently didn't think a pure ActionGirl is impossible; in the 50's manga, she is nervous but [[PluckyGirl brave enough]] to fight after she permanently loses her male heart[[/note]]. If her female heart is removed, she derides anything remotely feminine as "girly".
* ValuesResonance: When it first came out in 1953, ''Manga/PrincessKnight'' seemed to portray Sapphire as a {{Tomboy}} because of her stereotypically masculine interests, with the justification that she was mistakenly given a blue boy's heart by an angel. Nowadays, it's popular to interpret the character as transgender--despite the fact that the manga presents a very stereotypical portrayal of masculine and feminine interests.
%%* ViewerGenderConfusion: Sapphire for one.
%%* WhatDoYouMeanItsNotSymbolic: Plastic, despite being dimwitted and as pliable as his namesake, is eligible for the throne solely for being male.
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