The king (♔, ♚) is the most important piece in the game of chess. It may move to any adjoining square; it may also perform a move known as castling. If a player's king is threatened with capture, it is said to be in check, and the player must remove the threat of on the next move. If this cannot be done, the king is said to be in checkmate, 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 the endgame or, rarely, the middlegame. In algebraic notation, the king is abbreviated by the letter K among English speakers. The white king starts the game on e1; the black king starts on e8. Unlike all other pieces, only one king per player can be on the board at any time, and the kings are never removed from the board during the game. Placement and movement The white king starts on e1, on the first to the right of the queen 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, or 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 (see opposition) to give check, as that would put the moving king in check as well. The king can give discovered check, however, by unblocking a bishop, rook, or queen. Castling The king can make a special move, in conjunction with a rook of the same color, called castling. 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 as castling kingside or short castling (denoted 0-0 in algebraic