Chess

About the game

Chess is the classic strategy board game, here to play in the browser against the computer. You play White and make the first move; the goal is to checkmate the black king.

The rules are complete: castling, en passant capture, check, checkmate and stalemate. A game is also drawn when 50 moves pass without a capture or pawn move, or when the same position appears three times. Every pawn that reaches the last rank is promoted to a queen.

The computer uses alpha-beta search and looks a few moves ahead, making it an opponent for quick games with no clock pressure. If you win by checkmate, your score is the number of moves you made, and fewer is better. For a version with a die and cards, see Chess RPG.

How to play

1. Click a white piece to select it; the squares it can go to are highlighted.
2. Click a highlighted square to move. Only legal moves are shown, so a move that would leave your king in check isn't offered.
3. To castle, select the king and click the destination square two files away, when castling is available.
4. The computer answers right away with Black; the last move of each side appears below the board.
5. When your king is in check, the game tells you and highlights the king.
6. Use Undo to go back to your last move, along with the computer's reply.

Game modes

• 1 player. One player with White against the computer with Black. Checkmate wins; your result is the number of moves it took you to win.

Tips

• If your king is in check, only the moves that resolve the check are highlighted: select pieces until you find the defense.
• Before each move, look at the text below the board: it shows your last move and the computer's reply.
• Promotion is always to a queen, so taking a pawn to the last rank guarantees a second queen.
• Watch out for stalemate: if your opponent has no moves and is not in check, the game ends in a draw.

The pieces

Frequently asked questions