Back rank: For white, the first rank and for black, the
eighth.
Back rank mate: A checkmate delivered by a rook or queen
along a back rank in which the mated king is unable to move up the board
because the king is blocked by friendly pieces (usually pawns) on the second
rank.
Bad bishop: A bishop which is hemmed in by pawns of its
own color.
Blitz chess: A form of chess with a very small time
limit, usually 3 or 5 minutes per player. With the advent of electronic chess
clocks, it is often the case that the time remaining is incremented by 1 or 2
seconds per move.
Castling: A special move involving the king and one rook.
See
castling.
Center: The 4 squares in the middle of the board.
Checkmate: A position in which a player's king is in
check and the player has no legal move (i.e cannot move out of check). A
player whose king is checkmated loses the game.
Combination: A clever sequence of moves, often involving
a sacrifice, to gain the advantage.
En passant (from the french): The rule that allows a pawn
that has just advanced two squares to be captured by a pawn on the same rank
and adjacent file.
En prise (from the french): A piece that can be captured.
Usually used of a piece that is undefended and can be captured.
Exchange:
The capture of a pair of pieces, one white and the other black, usually
of the same type (i.e rook for rook, knight for knight etc).
The advantage of a rook over a minor piece. The player who captures a
rook while losing a minor piece is said to have won the exchange, and his
opponent is said to have lost the exchange.
Passed pawn: A pawn that has no pawn of the opposite
color on its file or on one of the adjacent files on its way to queening.
Pawn structure: Pawns being the least mobile of the
pieces, the position of the pawns influences the character of the game. The
type of placement of the pawns is known as the pawn structure.
Perpetual check: A player forces a draw by repeatedly
putting the opponent's king under check in such a way that the opponent cannot
avoid getting into check.
Pin: When a piece can not move because doing so would
expose a valuable piece, usually the king, to attack. See
Pin.
Promotion: Advancing a pawn to the eighth rank,
converting it to a queen, rook, bishop or knight. Promotion to a piece other
than a queen is called
underpromotion.
Protected passed pawn: A passed pawn that is supported by
another pawn.
Sacrifice: When one player voluntaily gives up material
in return for an advantage such as space, development (like forcing the
opponent into a particular move), or an kingside attack.
Skewer: An attack to a valuable piece to compel it to
move to avoid capture and expose a less valuable piece which can then be taken
by the attacker. Sometimes called a Thrust.
Smothered mate: A checkmate delivered by a
knight in which the mated king is unable to move owing to it being
surrounded (or smothered) by its own pieces. See
smothered mate.
Stalemate: A position in which a player's king is not in
check and the player has no legal move. A game is drawn if one of the kings is
stalemated. See
stalemate.
Tempo: An extra move, an initiative at development. A
player gains a tempo (usually in the opening) by making the opponent move the
same piece twice or defend one of his pieces. Pl: tempi.
Threefold repetition: The game is drawn if the same
position occurs three times with the same player to move, and with each player
having the same set of legal moves each time. (The latter includes the right
to take en passant and the right to castle).
Thrust: See Skewer above.
Touched piece rule: A player who picks up one of his
pieces (or touches it) is obliged to move that piece.
Triangulation: A technique used in king and pawn endgames
to lose a tempo and gain the opposition.