Theking (♔, ♚) is the most importantpiece in the game ofchess. It may move to any adjoining square; it may also perform, in tandem with therook, a special move calledcastling. If a player's king is threatened with capture, it is said to beincheck, and the player must remove or evade the threat ofcapture immediately, such as by moving it away from the attacked square. If this cannot be done, the king is said to be incheckmate, resulting in a loss for that player. A player cannot make any move that places their own king in check. Despite this, the king can become a strong offensive piece in theendgame or, rarely, themiddlegame.

White king

Black king

Inalgebraic notation, the king is abbreviated by the letterK among English speakers. The white king starts the game on e1; the black king starts on e8. Unlike all other pieces, each player can have only one king, and the kings are never removed from the board during the game.

The white king starts on e1, on the firstfile to the right of thequeen from White's perspective. The black king starts on e8, directly across from the white king. Each king starts on a square opposite its own color.

A king can move one square horizontally, vertically, and diagonally unless the square is already occupied by a friendly piece or the move would place the king in check. If the square is occupied by an undefended enemy piece, the king may capture it, removing it from play. Opposing kings may never occupy adjacent squares (seeopposition) to give check, as that would put the moving king in check as well. The king can givediscovered check, however, by unblocking abishop,rook, or queen.

The king can make a special move, in conjunction with a rook of the same color, calledcastling. When castling, the king moves two squares horizontally toward one of its rooks, and that rook is placed on the square over which the king crossed.

Castling is permissible under the following conditions:

• Neither the king nor the castling rook have previously moved.
• No squares between the two pieces are occupied.
• The king is not in check.
• None of the squares the king would move across or to are under enemy attack.

Castling with the h-file rook is known ascastling kingside orshort castling (denoted 0-0 inalgebraic notation), while castling with the a-file rook is known ascastling queenside orlong castling (denoted 0-0-0).

A king that is under attack is said to beincheck, and the player in check must immediately remedy the situation. There are three possible ways to remove the king from check:

• The king is moved to an adjacent non-threatened square. A player may not castle to get their king out of check. A king can capture an adjacent enemy piece if that piece is not protected by another enemy piece.
• A piece is interposed between the king and the attacking piece to break the line of threat (not possible when the checking piece is aknight orpawn, or when indouble check).
• The attacking piece is captured (not possible when in double check, unless the king captures).

If none of the three options are available, the player's king has beencheckmated, and the player loses the game.

In casual games, when placing the opponent's king in check, it is common to announce this by saying "check", but this is not required by the rules of chess. In tournament games, it is not usual to announce check; competent players are expected to know when they are in check.

A stalemate occurs when a player, on their turn, has no legal moves, and the player's king is not in check.

If this happens, the king is said to have been stalemated, and the game ends in adraw. A player who has very little or no chance of winning will often, in order to avoid a loss, try to entice the opponent to inadvertently place the player's king in stalemate (seeswindle).

In theopening andmiddlegame, the king will rarely play an active role in the development of an offensive or defensive position, with the notable exception of aking walk. Instead, it will normallycastle and seek safety on the edge of the board behind friendlypawns. In theendgame, however, the king emerges to play an active role as an offensive piece, and can assist in thepromotion of the player's remaining pawns.

It is not meaningful to assign a value to the king relative to the other pieces, as it cannot be captured orexchanged and must be protected at all costs. In this sense, its value could be considered infinite. As an assessment of the king's capability as an offensive piece in the endgame, it is often considered to be slightly stronger than a bishop or knight.Emanuel Lasker gave it the value of a knight plus apawn (i.e. four points on the scale ofchess piece relative value),^[1] though some other theorists evaluate it closer to three points. It is better at defending friendly pawns than the knight is, and it is better at attacking enemy pawns than the bishop is.^[2]

The king's predecessor is the piece of the same name inshatranj. Like the modern king, it is the most important piece in the game and can move to any neighboring square. However, in shatranj, baring the king is a win unless the opponent can do the same immediately afterward; stalemating the king is a win; and castling does not exist.

Unicode defines three codepoints for a king:

♔ U+2654 White Chess King

♚ U+265A Black Chess King

🨀 U+1FA00 Neutral Chess King

• Barden, Leonard (1980),Play better chess with Leonard Barden, Octopus Books Limited, pp. 9, 11, 12,ISBN 0-7064-0967-1
• Brace, Edward R. (1977),An Illustrated Dictionary of Chess, Hamlyn Publishing Group, p. 151,ISBN 1-55521-394-4
• Hooper, David;Whyld, Kenneth (1996) [First pub. 1992], "king",The Oxford Companion to Chess (2nd ed.),Oxford University Press, pp. 200–01,ISBN 0-19-280049-3
• Lasker, Emanuel (1934),Lasker's Chess Primer, Billings (1988 reprint),ISBN 0-7134-6241-8{{citation}}:ISBN / Date incompatibility (help)
• Ward, Chris (1996),Endgame Play, Batsford,ISBN 0-7134-7920-5
• FIDE Handbook: Laws of Chess

• Fianchetto variation of the King’s Indian DefenceArchived 2014-08-05 atarchive.today
• Piececlopedia: King by Fergus Duniho andHans Bodlaender,The Chess Variant Pages