Chess rules: checks, legal moves, and draws

A legal move follows the piece’s movement rules and leaves your own king out of check. That second condition matters: a move that wins a queen is still illegal if it exposes your king to a rook.

Respond to check first

You may escape a check by moving the king, capturing the checking piece, or blocking its line of attack when possible. In double check, a king move is required. Kings cannot stand next to one another, and a king cannot capture a protected piece.

Castling has additional conditions: neither the king nor that rook may have moved, the intervening squares must be empty, and the king may not start in, pass through, or finish in check. Our castling lesson walks through the details.

Separate the different draws

Stalemate means the side to move has no legal move and is not in check. A dead position is one in which neither side can ever checkmate by any legal sequence; king against king is a simple example.

Under FIDE rules, threefold repetition and 50 moves by each player without a pawn move or capture generally require a correct claim. Fivefold repetition and 75 such moves by each player bring automatic draws, with checkmate on the final move taking precedence over the 75-move rule. Repetition concerns the same position and legal possibilities, not simply moving a piece back and forth three times.

Learn the format you are playing

Touch-move, clock procedures, and penalties matter in tournaments. Online platforms handle some of these automatically and may implement draw claims differently. Consult the event rules before a competition; this lesson is a starting point, not the complete arbiter handbook.

The useful move-by-move habit is to check legality before quality. First establish which moves are possible; then decide which is best.

A move can follow the pattern and still be illegal

The white pawn appears to meet every special condition for en passant: it is on the fifth rank, and Black’s neighbouring pawn has just advanced two squares. Yet bxc6 would remove both blockers from rank 5. The rook on h5 would then attack White’s king on a5. The move is illegal because the ordinary king-safety rule still applies.

This example gives a useful order of operations. First determine how the piece is allowed to move. Then update the whole board, including any captured piece. Finally inspect your king. Stopping after the first step is the source of many apparent rules exceptions.

The same board is not always the same position

For repetition, piece placement alone is insufficient. The side to move and the legal possibilities must also match. A king that has moved away and returned may look unchanged on the board, but its castling right has been lost. That can distinguish positions that seem visually identical.

Similarly, a pawn move resets the count used for the 50-move rule even if it captures nothing. A capture resets it even if no pawn moves. Do not try to reconstruct these counts from the final arrangement of pieces; the game’s history matters.

When learning a rule, invent a pair of positions that differ in just one relevant condition. Compare castling with an attacked rook against castling through an attacked square. Compare no legal moves with check against no legal moves without check. These small contrasts make the boundaries of the rule memorable.