Chess

How chess is played

Two players, White and Black, move in turn on a board of 8 × 8 squares; White moves first, and each move moves one piece. The goal is checkmate: to attack the opposing king so that it cannot escape.

The board

The files are a to h, the ranks 1 to 8, and each player has a light square in the right-hand corner. White starts on ranks 1 and 2, Black on ranks 8 and 7. Each side has eight pawns in front and, behind them, from the corners in, a rook, a knight and a bishop on each side, then the queen on a square of her own colour (the white queen on d1, the black one on d8) and the king beside her (on e1 and e8).

The pieces

The king steps one square in any direction. The queen moves any number of squares along a rank, a file or a diagonal, the rook along a rank or a file, the bishop diagonally. None of them may pass another piece. The knight jumps in an L, two squares one way and one to the side, over anything in between. No piece may move onto one of its own. A piece captures by moving onto an opponent’s piece, which leaves the board. A piece attacks every square it could capture on. The king is never captured: checkmate ends the game first.

Pawns

A pawn only moves forward: one square, or two from its starting square if both are empty. It captures one square diagonally forward and never straight ahead, so a piece right in front of it stops it. At the far end of the board (rank 8 for White, rank 1 for Black) it must become a queen, rook, bishop or knight, as you choose; usually a queen. En passant: when an opposing pawn has just moved two squares and stopped beside your pawn, your pawn may take it by moving diagonally onto the square it passed over, but only on the very next move.

Castling

Castling takes the king to safety and brings a rook into play. Once per game the king may move two squares towards either of its rooks, and that rook jumps over it to the square beside it. Neither the king nor that rook may have moved before, the squares between them must be empty, and the king may not be in check, cross an attacked square or land on one. Here you castle by moving the king two squares.

Check and checkmate

A king that is attacked is in check, and the player must end the check at once: move the king, block the attack or capture the attacker. No move may leave the own king attacked, so a pinned piece, one that shields its king from an attack, cannot leave that line. A player in check without any legal move is checkmated and loses.

Draws

A player who is not in check but has no legal move is stalemated: a draw. The same position three times, fifty moves each without a capture or a pawn move, and too little material to mate (such as king and bishop against king) are draws too.

Handicaps

Against a much stronger opponent the old masters gave odds: the stronger side starts without a piece. Here the bot can give them, or you can (the setup’s "Handicap"). Pawn and move (no f7 pawn; the receiver plays White and moves first), pawn and two moves (the receiver has played 1.e4 and moves again), a knight (b1), a rook (a1, no queenside castling), two knights, a rook and a knight, or the queen; except for the two pawn odds the giver plays White. Philidor played most of his games at odds in the 18th century; today engines give knight or rook odds to grandmasters.

More games

Chess and variants

• Chess960 · Fischer random chess: the back rank starts in one of 960 setups.
• Antichess · Losing chess: give away all your pieces, captures are compulsory.
• Atomic chess · Every capture is an explosion that clears the pieces around it.
• Crazyhouse · Captured pieces change sides and can be dropped back onto the board.
• Duck chess · After every move you move the duck, which blocks everyone. No check.
• Fog of War · You only see where your pieces can move. Capture the king to win.
• Friendly Chess · Nothing is captured: pieces unite and set off chain reactions.

The chess family

• Chaturanga · India’s ancient chess, the root of the family: take the king to win.
• Shatranj · The medieval ancestor of chess, with a weak ferz and a jumping alfil.
• Makruk · Thai chess: a slow, strategic game with a counting rule.
• Ouk Chatrang · Cambodian chess: Makruk with a leap for the king and the met.
• Sittuyin · Burmese chess: set up your pieces, then promote on the diagonals.
• Xiangqi · Chinese chess: a river, palaces and a cannon that jumps to capture.
• Janggi · Korean chess: no river, palace diagonals and a cannon that always jumps.
• Shogi · Japanese chess: captured pieces return to the board on your side.
• Minishogi · Shogi on a 5 × 5 board: six pieces a side, short and sharp games.

More players

• Chaturaji · India’s four-handed chess: kings can be captured, captures score.
• Four Seasons Chess · Alfonso X’s chess for four from 1283: four seasons, the last king wins.
• Three-player chess · Three armies on a hexagonal board: you against two bots.
• Four-player chess · Four armies on a cross-shaped board: in teams or all against all.
• Eight-player chess · Eight armies on a board of 516 squares: all against all, in pairs or four against four.