• Castle: A simultaneous move (the only one in chess) whereby a previously unmoved King moves 2 squares toward an unmoved Rook and the Rook is moved to the other side of the King

  • No piece can be between the King and Rook on the move of castling

  • If your king is in check, it cannot castle

  • If there is a piece of your opponent's that is attacking any of the squares of which your king passes through and lands on in a castle, then you cannot castle

• Check: A move which attacks the opposing King

• Checkmate: A move which attacks the opposing King, and which the opponent cannot get out of

• Defense: An opening played by Black, or a series of moves taken to protect a piece or position which is under attack

• Discovered Check: A check given by a line-piece when a shielding piece or pawn is moved out of the way

• Endgame: The stage of the game with few pieces or when Queens are exchanged and the middle game is over

• En Passant: A special method of capturing, only available to a pawn on its fifth rank

  • The opponents pawn must move two squares forward right next to your pawn​

  • You capture their piece and move your piece one square behind their piece

  • This must be done right after the move is available; it expires if you don't do it at the first moment you can

  • Can be done multiple times in a game

• File: The eight vertical columns on the board, numbered a to h

• Fork: A double attack when one piece, such as a Knight, attacks two or three pieces at once

• Gambit: A chess opening in which a player offers a pawn (or more) for fast development and an attack

• Major Piece: Queen or Rook

• Middlegame: The part of the game which follows the opening

• Minor Piece: Bishop or Knight

• Notation: The method of writing down chess, moves which involves rank and file and piece

• Opening: The start of the game, about a dozen moves

• Pin: When a piece does not move because to do so would expose a more valuable piece to capture

• Promotion: Promotion is what happens when a pawn reaches the other side of the board (that is, the 8th rank) and cannot move further. Then it becomes any other piece on the board, except the king.  Players usually promote their pawns to a Queen

  • Can occur multiple times in a game​

  • Becomes another piece of the player's choice and behaves like it for the rest of the game (or until captured)

• Resign: To concede loss of the game. A resignation is usually done by knocking over one’s King, stopping the clock, offering a handshake or saying “I resign”

• Sacrifice: The intentional loss of material to get a more important result

• Stalemate: Where a player is not in check, but has no legal moves. It is a draw in modern chess

• Threefold Repetition: A player can claim a draw if the same position occurs three times, or will occur after their next move, with the same player to move. The repeated positions do not need to occur in succession

• Zugzwang: A position, usually in an ending, where the player to move loses because they must move

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