The king starts each game on the back rank on the e-file. (Do you know how the squares on a chessboard are labeled? If not, see the article "How to Play Chess.") Because the queen starts on a square that matches its color, the king starts on the opposite color. Thus, the white king starts on a dark square, while the black king starts on a light square.
Because it is next to its queen and the kingside bishop and is blocked by a row of pawns, it cannot move initially in a game. Because its safety is also important, moving the king initially in a game should be limited to a special move known as castling, as described below. As you can see, White's king starts on e1, and Black's king starts on e8.
Much like the queen, the king can move in any direction: horizontal, vertical, or diagonal. However, compared to the movement of other pieces, the king’s movement is very limited. Unlike the queen that can move many squares as long as it is not blocked by another piece (unless it is capturing it), the king can usually move just one square.
However, in a special move known as castling, the king can move two squares in concert with a rook. The movement can take place on the queenside, but the kingside is the more typical choice. After the king moves, the rook is placed next to it away from the corner of the chessboard. After this move has been made, the king is typically insulated by a line of pawns in front of it and protected by the rook at its side. Watch this video for more details about castling.
The king might look like it's in jail after castling, but it is actually protected by a rook at its side and a row of pawns in front of it.
In addition to the special move, another characteristic about the king makes it very special. First, it cannot be captured unlike every other piece on the board. The king is the only piece that cannot be taken off the board or captured.
When the king is attacked, it is “in check.” When this occurs, the king must get out of check. There are only three ways for the king to get out of check. One is to capture the enemy piece that is putting the king in check. Another way is to move a piece to block the check. A third way is to move the king to a safe square where it is no longer in check. The king can never move in check (such a move is illegal). In the following illustration, the king is in check. How many ways can it get of check?
Unlike other pieces that have a value in points (such as the rook that is worth five points), the king is assigned no points because it is indispensable for playing a game. If a king in check cannot get out of check, the game is over. Sometimes a player signifies that they are resigning the game by tipping their king over.
Although the king really doesn't measure in value like the other chess pieces because it is indispensable, this king wants to show how that it's worth more than any other piece.
The pawns on the second and seventh ranks help to protect a king. However, be alert to the weakness of the pawns on the f2- and f7-squares that are protected by only a king when a game begins. Sometimes these squares are where quick checkmates occur, such as the 4 move checkmate.
See this example of Fool's Mate, where the weakness of the f2-square leads to a quick checkmate.
Do you know how important the king can be in the endgame? When most of the opponent’s pieces have been removed, the king is less vulnerable to attack. In addition, the king may be able to attack an opponent’s weak pawns or block a pawn from advancing. It may also be able to control important squares, protect pieces, and limit the movement of the opponent’s king.
Consider this: when your king is on a central square of the board, the opponent’s king can’t be placed in the center. In an endgame, activating your king is as important as preventing the opponent’s king from becoming active. Cutting off the enemy king is a critical endgame technique. See the article “How to Win by Using Your King” to learn more.
Now you know the role of the king in a game of chess. It is indispensable. You also know where it starts a game, how it moves, and how it can be protected.