based in the rules of chess. A grid representing a subsection of a chessboard is shown, and the puzzle solver must place a certain number of queens on it so that none of them threatens the others: that is, none can share a rank, file or diagonal. The standard puzzle is "Place N
queens on an N
board," with a value of N between four and the standard eight of a full board. The puzzle can't be solved for N = 2 or 3.
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- A room-sized version of this puzzle appears in the short story "The Most Precious of Treasures" by Desmond Warzel. In a case of Only Smart People May Pass, the protagonists must solve it to enter the next room of the dungeon; however, it's not intended to be difficult. It's really a test of sentience, not intelligence.
- In Professor Layton and the Curious Village, the puzzles given by the chess player in the tavern are a N=4 and N=5, and one of the bonus puzzles is a full 8. The hints for the bonus puzzle tell you to not bother buying more hints, as you should know how to do it by that point.
- The 7th Guest has the Eight Queens puzzle in the games room on the second floor.
- There's also an "upgraded" version involving Eight Super-Queens, which can also move like Knights. Good Luck.
- Splinter Cell Double Agent has a 3D version of this. Genre Shift, anyone?
- Empress of the Deep: The Darkest Secret (an IHOG) has one in the Vault of War.
- In Kheops Studios' spiritual successor of Safecracker, the N=6 version appears on one of the safes in the attic.
- Another N=6 variant appears in the flash game Tower Core, inside one of the three towers.