Chess rules
These rules follow the FIDE Laws of Chess in force since 1 January 2023. Article numbers are in brackets.
The board and the goal
White moves first, then the players take turns (1.2). You win by checkmate: attacking the opponent's king so that they have no legal move (1.4, 5.1.1).
You may never make a move that leaves your own king under attack (3.9.2).
The board sits with a light square in each player's near right-hand corner (2.1).
How the pieces move
The rook moves any distance along its rank or file, the bishop along a diagonal, and the queen along either (3.2–3.4). None of the three may pass over another piece (3.5).
The knight goes to one of the nearest squares not on its own rank, file or diagonal — the far corner of an L (3.6). The no-passing rule covers only the rook, bishop and queen (3.5), so pieces in between do not block a knight.
The king moves one square in any direction (3.8.1).
Pawns
A pawn moves one square straight ahead into an empty square, or two on its first move if both are empty (3.7.1, 3.7.2). It captures one square diagonally forward (3.7.3).
En passant
If an enemy pawn has just advanced two squares and stopped beside your pawn, you may capture it as if it had moved one. Only on the very next move (3.7.3.1, 3.7.3.2).
exd6, but only now.Promotion
A pawn reaching the far rank must become a queen, rook, bishop or knight of its colour, and the new piece works at once (3.7.3.3, 3.7.3.5). The choice is not limited to pieces already captured (3.7.3.4), so a player can have two queens.
e8=Q: the pawn steps onto e8 and is replaced by a queen.Castling
The king moves two squares towards a rook, and that rook moves to the square the king crossed (3.8.2).
When you can never castle again
Once the king has moved, castling is gone for good on both sides. Once a rook has moved, it is gone on that rook's side (3.8.2.1). Moving back to the starting square does not bring it back.
When you cannot castle right now
- Your king is in check.
- The king would cross or land on a square an enemy piece attacks.
- Any piece stands between the king and the rook (3.8.2.2).
Only the king's squares count. On the queenside the rook crosses b1, and castling is allowed even if b1 is attacked.
O-O is illegal for now. Neither the king nor the rook has moved, so it becomes legal again once f1 is safe.Check
A king is in check when an enemy piece attacks it — even a piece that could not actually move there because it is pinned to its own king (3.9.1). You must get out of check at once (3.9.2), in one of three ways:
- move the king to a square that is not attacked;
- capture the checking piece;
- put a piece in between. This does not work against a knight, a piece right next to the king, or two checks at once.
How a game ends
A win: checkmate (5.1.1), the opponent resigns (5.1.2), or the opponent runs out of time (6.9).
A draw: stalemate, when the player to move is not in check and has no legal move (5.2.1); a dead position, where neither side can ever checkmate (5.2.2); or agreement, once both players have made at least one move (5.2.3).
Checkmate or stalemate?
| Checkmate | Stalemate | |
|---|---|---|
| In check? | Yes | No |
| Any legal move? | None | None |
| Result | Win | Draw |
Resigning or running out of time is a draw instead of a loss when the opponent could not checkmate by any series of legal moves (5.1.2, 6.9).
Not enough pieces to mate
The Laws have no list of "insufficient material". The test is the dead position of 5.2.2: could any series of legal moves, however bad, end in mate? King against king, or king and one bishop or one knight against king, never can.
Two knights against a lone king are different. Mate cannot be forced, but it can happen if the defender blunders, so under FIDE rules the game goes on. Some sites score it as a draw instead.
Repetition and the 50-move rule
A player may claim a draw when the same position appears for the third time, or when both sides have made 50 moves without a pawn move or a capture (9.2, 9.3). At five repetitions or 75 moves the draw needs no claim (9.6).
Positions are the same only if the same player is to move, the same pieces stand on the same squares and every possible move is the same. If castling or en passant was possible the first time and not later, they count as different positions (9.2.3).
Rules for a physical board
Touch-move — a piece you deliberately touch must be moved (4.3) — and pressing your clock after each move (6.2.1) belong to over-the-board play. On a screen a move counts only when you drop or tap it, and the clock switches by itself.
How this site applies them
There is no arbiter to hear a claim, so the game ends in a draw the moment the third repetition or the 50th move is reached.
It recognises three kinds of position where mate is impossible: kings alone; a king and one bishop or knight against a king; and kings with only bishops, all on squares of one colour.
After a resignation or a flag fall, it scores a draw only when the opponent has a lone king. Rarer positions where mate is impossible, such as locked pawn chains, are scored as a loss.