The player controlling the white pieces is named “White”; the player controlling the black pieces is named “Black”. White moves first, then players alternate moves. Making a move is required; it is not legal to skip a move, even when having to move is detrimental (zugzwang). Play continues until a king is chexmated, a player resigns, or a draw is declared, as explained below. In addition, if the game is being played under a time control players who exceed their time limit lose the game.
The official CHEX rules do not include a procedure for determining who plays White. Instead, this decision is left open to tournament-specific rules or, in the case of non-competitive play, mutual agreement, in which case some kind of random choice is often employed. A common method is for one player to conceal a piece (usually a pawn) of each colour in either hand; the other player chooses a hand to open, and receives the colour of the piece that is revealed.
Movement – Basic moves
Each type of CHEX piece has its own method of movement which closely follow that of traditional chess pieces. A piece moves to a vacant square except when capturing an opponent’s piece. Except for any move of the knight and castling, pieces cannot jump over other pieces. A piece is captured (or taken) when an attacking enemy piece replaces it on its square (en passant is the only exception). The captured piece is thereby permanently removed from the game. The king can be put in chex but cannot be captured.
The queen moves any number of vacant squares in a horizontal, vertical, or diagonal direction.
A rook moves any number of vacant squares in a horizontal or vertical direction. It also is moved when castling.
A bishop moves any number of vacant squares in any diagonal direction.
A knight moves to the second nearest field not on the same rank, file, or diagonal. (This can be thought of as moving two fields horizontally then one field vertically, or moving one field horizontally then two fields vertically—i.e. in an “L” pattern.) The knight is not blocked by other pieces: it jumps to the new location.
Pawns have the most complex rules of movement:
A pawn moves straight forward one square or field, if that square or field is vacant. If it has not yet moved, a pawn also has the option of moving up to three squares straight forward if the field ahead is empty. Pawns cannot move backwards.
Pawns are the only pieces that capture differently from how they move. A pawn can capture an enemy piece on either of the two squares diagonally in front of the pawn (but cannot move to those squares if they are vacant).
The pawn is also involved in the two special moves en passant and promotion.