''Nazo no Murasamejō'' (loosely translated: ''The Mysterious Murasame Castle'') is a medieval Japanese fantasy video game created by Nintendo and released in 1986 as the second original title for the FamicomDiskSystem, after ''VideoGame/TheLegendOfZelda'', to which it has some resemblance. The game has been occasionally rereleased, eventually coming to Europe as well.

The game takes place during the Edo period, where Murasame and four neighboring castles have been possessed by a demonic force. It falls to a young swordsman named Takamaru to defeat Murasame.
* ColourfulThemeNaming: The four castles besides Murasame, Aosame, Akasame, Ryokusame and Momosame, are named after Japanese colors.
* ContinuingIsPainful: Most powerups are lost upon death.
* FlipScreenScrolling: Throughout the game.
* HeyItsThatSound: The Raccoon Mario transformation sound effect from ''Super Mario Bros. 3'' originated in this game.
* ImpossiblyCoolWeapon: Getting enough shuriken upgrades results in shuriken with explosive lightning. [[WebAnimation/ZeroPunctuation Yahtzee would have loved it.]]
* MarthDebutedInSmashBros: A minigame based on this appears in ''VideoGame/NintendoLand'', even though it's never been released outside of Japan. Takamaru and the eponymous castle similarily appeared in VideoGame/SamuraiWarriors 3.
* NintendoHard: As with all games of [[The8BitEra the era]].
* TheVeryDefinitelyFinalDungeon: The titular Murasame Castle, where the floor is black and the walls are NothingButSkulls.