Aka ''Ribon no Kishi''[[note]]Literally, Ribbon Knight or Knight of the Ribbon[[/note]] and ''Choppy and the Princess''.

The story of Sapphire, the princess of Silverland, who must pretend to be a prince.

In Heaven, the souls of unborn children are being prepared for their births. Tink, an inexperienced apprentice angel, accidentally gives a child who will be born female both a pink "girl's" heart and a blue "boy's" heart. When this is found out, it's too late to fix the mistake, so Tink is banished to Earth in a weak mortal body to watch over the twin-hearted child.

Meanwhile, in Silverland, a vaguely medieval kingdom, the King learns to his dismay that the Queen has given birth to a girl, and due to complications cannot have another child. Women cannot inherit the throne, and the King knows that his closest male relative, Duke Duralumin, is a wicked man who would oppress the people. So the King pretends that Sapphire was born male, with only a handful of close advisors knowing the truth.

Thanks to her dual nature, Sapphire is equally adept at male and female activities (even if the latter must be taught in secret). The story picks up in Sapphire's early adolescence, as Duke Duralumin steps up his attempts to prove the Prince to be a girl, and Tink finally finds Sapphire in the mortal world. And it's a good thing Sapphire has a new ally, as the Duke is not the only force that threatens Silverland.

''Ribon no Kishi'' was created by Creator/OsamuTezuka in 1953, and is one of the earliest {{shojo}} manga. The original manga series ran from 1953 to 1956 and proved popular enough to be granted a sequel, ''Twin Knights'', starring [[SpinOffspring Sapphire's daughter]] Princess Violetta on her search for her lost twin brother [[GenderBlenderName Prince Daisy]]. During the 60's Tezuka also made a TV anime adaption and an extended remake of the manga. Both versions followed roughly the original story up until close to its ending where they split off in their own directions. The new manga had Sapphire encountering the pirate Blood, fellow swords-woman Friebe and [[Myth/ClassicalMythology the goddess Venus]], all while overcoming [[spoiler: the permanent loss of her boy-heart]]. The anime also played around with some of these ideas, but quickly put them aside in favor of a longer StoryArc involving a new villain, Mr. X.

The anime was broadcast in the United States as ''Princess Knight'' or ''Choppy and the Princess'', the latter being at first the title of a short movie made by mashing together three of the episodes. Distribution of the American version was spotty at best, and it wasn't until 2012 that the show got a proper DVD release. The 60's manga has received an English language two-volume collected release from Vertical inc in 2011 and a similar release of ''Twin Knights'' finally saw the light of day in 2013.
!!This series provides examples of:
* ActionGirl: Sapphire and Friebe. Violetta and Emerald in Twin Knights.
* AdultFear: Sapphire and Franz are terrified when they learn that their infant son has disappeared. They have the castle searched from top to bottom for him, and even search the ''moat''.
* AntiAntiChrist: Hecate, Satan's daughter, who's secretly good, or at least no worse than mischievous.
* BackFromTheDead: [[spoiler:Sapphire's parents]], in the finale of the anime, and Sapphire herself thanks to Venus's help.
* BadIsGoodAndGoodIsBad: Hecate, while not truly evil, was raised by Madame Hell (or Mephisto, depending on the version) and has some very disturbing ideas of what constitutes harmless fun.
* {{Bifauxnen}}: Sapphire can pull off pretending to be a prince because she resembles one.
* BigBad: Mr. X. [[EvilerThanThou Even Satan pales in comparison in terms of sheer evil]]. Though in the manga, Madame Hell is the Big Bad.
* {{Bishonen}}: See the entry for "DudeLooksLikeALady", below.
* TheChewToy: Sir Nylon. His constant misfortune gets more amusing.
* ClingyJealousGirl: Venus
* DamselInDistress: Although more often than not, it evolves into DamselOutOfDistress.
* DeusExMachina: Played with, due to the nature of the plot.
** Played straight when [[spoiler:a bunch of angels come to help Tink to fight Madame Hell]] or when [[spoiler:God himself]] helped out briefly.
** ''Deconstructed'' when [[spoiler:the help of Venus makes everything worse since help her isn't for free and [[DeconReconSwitch almost]] ruined the Happy Ending.]]
* TheDogBitesBack: [[spoiler:In the anime Sir Nylon, Duralumin's luckless henchman, finally snaps from the abuse and kills his boss, ruling Silverland for a very brief time as a drooling madman and puppet of Mr. X.]]
* DrivenToSuicide: [[spoiler: Duke Duralumin kills himself when he thinks his son is dying.]]
* DudeLooksLikeALady: When Sapphire temporarily loses her female heart and turns into a guy, she looks exactly the same as she did as a girl.
* EasyAmnesia: Sapphire temporarily loses all her memories after she's brought back from the dead.
* EvenTheGirlsWantHer: Sapphire's crossdressing earns her a few crushes from oblivious girls, most notably Friebe, who even makes it to the altar with Sapphire before she learns the truth.
* EverythingsBetterWithPrincesses: Sapphire is one.
* FantasyKitchenSink: A really weird example; apparently the Abrahamic {{God}} and the [[Myth/ClassicalMythology Greek gods]] exist in the same universe.
* FeministFantasy: Girls can't inherit the throne in this setting but due to a quirk in the MagicalUnderpinningsOfReality, Sapphire can.
** In ''Twin Knights'', Silverland's society has progressed enough that half of the kingdom is certain that Princess Violetta would be a better heir than Prince Daisy. Also, unlike ''Princess Knight'', Violetta's aptitude for sword fighting and other traditionally unlady-like behavior isn't attributed to her having a "boy's heart".
* FluffyCloudHeaven: Where Tink is from and the unborn souls of children are.
* ForgotICouldChangeTheRules: The king finally wants to change the law to allow Sapphire to succeed him, but is kidnapped to stop it.
* FriendToAllLivingThings: Sapphire has many cute animal friends.
* GenderBender: Sapphire is female, but has both male and female "hearts". At one point she loses her female heart and turns into a man.
* GoodHurtsEvil: Crucifixes and other holy items cause great pain to demons.
* GoOutWithASmile: [[spoiler: Tiln the Dayfly]] in Twin Knights.
* HeirClubForMen: If this were not the case, then Sapphire's dual identity would not be necessary.
* HeroicSacrifice: [[spoiler:Blood retrieves a potion to save Sapphire's life at the cost of his own life. Although it turns out [[ShaggyDogStory he brought it back just a few moments too late]].]]
** [[spoiler: Emerald intends to use a similar potion to save Violetta]] in Twin Knights, [[spoiler: but the mother wolf saves her in turn by taking her place.]]
* HotBloodedSideburns: Blood.
* InadequateInheritor: Duke Duralumin promotes his mentally disabled son Plastic for the throne in Saphire's place, seeking to rule from behind the scenes.
* JerkassGods: Venus, a goddess that becomes a villain out of jealousy.
* KilledOffForReal: A lot of characters including [[spoiler: the King (in the manga), Blood, Hecate, Eros, Madame Hell, and Duke Duralumin]].
** In Twin Knights: [[spoiler: Papi the Deer, Slobb, Tiln the Dayfly, Begonia the Witch, the mother wolf, Prince Black, Duchess Dahlia and probably the Duke.]]
* KnightOfCerebus: Mr. X makes things a lot more serious.
* LadyLand: Black Pearl Island.
* LaughingMad: [[spoiler: Friebe has a brief fit of hysterical laughter when she finds out that the boy she's about to marry is actually a girl.]]
* LargeHam: Duke Duralumin, [[LampshadeHanging he even has a portrait of himself]] on which he's MilkingTheGiantCow.
* LongLostRelative: [[spoiler:Captain Blood is the older brother of Prince Franz! Who'd have guessed?]]
* LovesMyAlterEgo: Prince Franz loves Sapphire's female disguise but hates Prince Sapphire due to a misunderstanding.
* MagicFeather: [[spoiler: Sapphire's boy heart]] in the 60's manga. [[spoiler: The loss of it initially cripples her with fear, but she eventually learns to be just as brave without it.]]
* MaskPower: During a period when Sapphire was supposed to be imprisoned, she snuck out a secret passage and donned a mask to be the Phantom Knight, who fought crime and oppression.
* MurderInc: The Assassin's Club.
* TheMusical: In 2006, idol group MorningMusume made a musical adaptation with an all-female cast, aided by [[{{Takarazuka}} the Takarazuka Revue]].
* NiceHat: Sapphire often wears a magnificently large hat.
** She dons it again in ''Twin Knights'', when [[spoiler:she and Violetta are imprisoned and she takes the opportunity to give her daughter swordfighting lessons]]. Violetta also has a similar one.
* NoOntologicalInertia: Madam Hell is reminded at one point her flesh-to-stone spell will be reversed if she dies. [[spoiler: Sadly, this also applies to Hecate, as her mother literally ''made'' her using magic.]]
* ObfuscatingInsanity: [[spoiler: Marquis Oolong pretends to be a nutcase so that if any of his underlings plot to overthrow him, they'll be less covert about it and he'll be able to root them out.]]
* PeacefulInDeath: The copse of [[spoiler: mother wolf]], in Twin Knights. is found with a peaceful smile on her face.
* PeekABangs: Parpa and Friebe.
* PinkGirlBlueBoy: The hearts in heaven are colored this way.
* PostClimaxConfrontation: [[spoiler:In the manga remake, Venus takes over as BigBad once Madame Hell and Duke Duralumin [[CharacterDeath are out of the picture]], and serves as the final obstacle of Sapphire's and Franz's love.]]
* PunchClockVillain: Eros often disapproves of her mistress Venus's jealousy -- motivated plots, and alternates between following orders because it's her job and secretly sabotaging Venus's plans while hoping that Venus won't find out.
* RaisedAsTheOppositeGender: Princess Sapphire is known as ''Prince'' Sapphire because it was the only way to keep the kingdom out of the evil duke's hands.
** A very interesting case happens in the sequel. To try to convince the kingdom that Prince Daisy had be safely found, Franz ordered Violetta to alternate between living as a girl and a boy. Unfortunately, the BigBad does catch on that the "prince" is never around when the princess is.
* ReallySevenHundredYearsOld: Tink looks like a little kid, but since he's [[OurAngelsAreDifferent an angel]] it's safe to assume he's much older.
* RebelliousPrincess: Hecate is an odd case because she's technically the princess of Hell and she frequently rebels against her mother's plans and helps out the people that her mother is victimizing.
* RecursiveCrossdressing: Sapphire sometimes wore a blonde wig and a gown to impersonate a girl with a nebulous relationship to the royalty of Silverland so that she could woo Prince Franz.
* {{Roma}}: Emerald is the free-spirited Queen of the Gypsies in ''The Twin Knights''. She wears a tiny dress, dances wildly, and hates the thought of living by rigid social rules. There's also Mercedes, a hag-like fortuneteller and potion maker, and various other stereotypically-dressed types. Of note is that Emerald claims "Gypsies are above all else devout!"
* RoyalsWhoActuallyDoSomething: [[spoiler: Oolong.]]
** [[spoiler: Plastic too, immediately after he swallows Sapphire's boy heart. In fact, the first thing he does is start to undo his father's evil deeds, then changes Silverland's outdated laws for the better and finally, paves the way to reinstall Sapphire as the righteous king. All what he wants in exchange is mercy for his father.]]
** Sapphire, among other things, heads a kingdom-wide revolution to get the women equal rights.
** Hecate, as seen above.
** In ''Twin Knights'', Princess Violetta sets out to find her long-lost twin brother [[spoiler:to free her parents from prison and stop the usurpers taking over the kingdom]].
* {{Satan}}: Also known as Mephisto. He desired, among other things, to steal Sapphire's unique twin-hearted soul. In his earthly form, he possessed powerful magic and NighInvulnerability, but was deathly afraid of angels, retreating whenever Tink blew his horn and occasionally turning him into a ButtMonkey.
* SmugSnake: Sir Nylon. Mrs. Hell (who appears in the third release published by Nakayoshi and replaces Satan's role) also qualifies.
* SweetPollyOliver: Sapphire, interestingly with no name change necessary.
* TakenForGranite: [[spoiler:Sapphire's mom, and later on lots of people in the vicinity of the royal castle of Silverland.]]
* {{Tomboy}} surprisingly, it is not Saphire, whose princely finery still marks her out as a dandy, but Hecate who is dressed in stereotypical 1950's tomboy garb.
* TookALevelInBadass: Plastic, after [[spoiler:accidentally swallowing Sapphire's boy heart]].
* TropeCodifier: This series codified the "[[{{Bifauxnen}} princely]] crossdressing heroine" trope that was later featured in ''Manga/RoseOfVersailles'' and ''Manga/RevolutionaryGirlUtena''.
* VoluntaryShapeshifting: Hecate can change into a variety of animals and creatures.
* WaifFu: With the HandWave of Sapphire's "male heart", because [[ValuesDissonance it's not like a girl could be competent at martial arts]].
* WhatDoYouMeanItsNotSymbolic: Plastic, despite being dimwitted and as pliable as his namesake, is eligible for the throne solely for being male.
* WholesomeCrossdresser: Sapphire pretends to be a boy out of political necessity.
** Her daughter is forced to do the same in the sequel, to convince the kingdom that her brother, Prince Daisy, is still around. Sapphire, who doesn't fondly remember her days of living as a boy, is immensely sorry to subject her daughter to the same fate, though Violetta holds up pretty well.