Chess

How to play

1. An 8 by 8 board; each side has a king, a queen, two rooks, two bishops, two knights and eight pawns. White moves first; colours are drawn for the first game and then alternate.
2. The king moves one square any way; the queen any distance along a line or diagonal, the rook along a line, the bishop along a diagonal, and none of them jumps. The knight moves in an L and jumps over pieces.
3. A pawn moves one square forward, or two from its starting square, and captures one square diagonally forward. It may take a pawn that just moved two squares past it en passant, on the very next move only. On the last rank it is promoted to a queen, rook, bishop or knight.
4. Castling: the king moves two squares towards a rook and the rook jumps to its other side, if neither has moved, nothing stands between them, the king is not in check, and it neither crosses nor lands on an attacked square.
5. Check: when your king is attacked you must save it, and no move may leave your own king attacked.
6. Each player's clock runs only on their turn, with no increment. You choose the clock and the bot's level: easy, medium or hard.

Winning and draws

• You win by checkmating the other king, when your opponent resigns, or when their clock runs out.
• Draws: stalemate (no legal move and not in check), agreement (each player may offer three times a game), fifty moves by each side with no pawn move and no capture, or the same position three times.
• It is also a draw when neither side has enough to mate: a lone king, or a king with one bishop, or with one or two knights. If a clock runs out and the opponent has only that, it is a draw, not a loss.