Mystery Chess is a game of logical induction (and possibly strategy) for 3 players. The first two players play against each other, while the third player, known as the Grandmaster creates and enforces the rules of the game.

The game of Mystery Chess is played on a standard chess board with the standard setup of pieces. The player who plays as white goes first, as in regular chess.

Before the game begins, the Grandmaster must use his infinite chess aura to bend the fabric reality to his will. He must aquire a tablet of stone (or a piece of paper), and inscribe therupon the rules of the game.

For a novice Grandmaster, this may consist of simply modifying the rules of chess by a small amount. For example, he could create a rule that a pawn may exhibit cowardice, and flee from the face of danger by moving one square backwards. An intermediate Grandmaster may implement a new moveset for every piece in the game. An expert Grandmaster knows no limits whatsoever: He may implement any manner of abomination his mind can concieve, triggered by any action, game state, or senses from beyond the realm of the chess board.

Player 1 begins by attempting to move one of their own pieces to a new location on the board. The Gamemaster will then take one of two actions: He can reject the move, causing the piece to return to it's original location (Signalled by a "No","Nope", or similar), or he can accept the move and update the board accordingly, killing or moving any pieces as specified by his rules.

No matter if the move is rejected or accepted, the turn passes to Player 2. They may then attempt a move of their own.

Play continues until one player has eliminated all of the opposing pieces, at which point they are crowned the winner. At this point, the Grandmaster must reveal his secret rules, and the players have the opportunity to disparage him.