Chess

Check & Checkmate

Since the object of the game is to capture the king, players are obligated to protect their kings at all costs. If a piece threatens to capture the opponent's king, that king is said to be "in check," and its owner must do something to protect the king at once. In fact, it is illegal to make a move that leaves or puts one's own king in check.

There are three possible ways to get out of check:

• Move the king to a square where it is not under attack.

• Interpose a piece between the king and the attacking piece, blocking the line of attack (this only works if the checking piece is a bishop, rook, or queen).

• Capture the piece that is attacking the king. In the below image, the knight can capture the bishop that is attacking the king.

If none of these methods are possible, the king isn't just in check--the king is checkmated, and the game is over. Note: in the below image the knight cannot move. Doing so would place its king in check by white's rook.

Stalemate

Sometimes there's a position in which a king is not in check, and its owner is supposed to make the next move, but any move will put the king in check.

For example, in the above diagram, if it's Black's turn in this position, he or she has no legal move, and is said to be "stalemated." A stalemate is a draw--neither player wins or loses.

Other Draws

• Agreement: Players may agree to offer a draw at any time.
• The 50-move rule: If each player makes 50 moves without a piece being captured or a pawn being moved, the game is a draw. (Exceptions to this rule have been added over the years to allow players more moves in which to win in certain positions, but it's safe for most players to remain ignorant of these very rare situations.)
• Through a repetition of moves: If a position is repeated three times (not necessarily consecutively) when it is the same player's turn to move, the game is a draw.
• Insufficient mating material: If neither player has enough pieces ever to be able to checkmate the other, the game is a draw. This would be true, for example, if only the two kings were left on the board, or if one player had only a king and a knight and the other only a king. A king and a rook, though, are enough to checkmate a king--which means that a king and pawn are enough to win provided the pawn can be promoted.

Resigning

A player may resign (concede the game) at any time.