Chess rules

Setting up

An 8×8 board with a light square at each player's bottom-right. Each side has a king, a queen, two rooks, two bishops, two knights and eight pawns. White moves first; each queen starts on her own colour.

How the pieces move

• King: one square in any direction.
• Queen: any distance in a straight or diagonal line.
• Rook: any distance along ranks and files.
• Bishop: any distance diagonally.
• Knight: an L shape — two then one — and may jump over pieces.
• Pawn: one square forward (two from its start square), capturing one square diagonally forward.

Special moves

• Castling: the king moves two squares toward a rook and the rook jumps over. Neither may have moved, nothing may stand between them, and the king may not be in, pass through or land in check.
• En passant: a pawn that has just moved two squares can be captured as if it had moved one, by an enemy pawn beside it, on the very next move only.
• Promotion: a pawn reaching the far rank becomes a queen, rook, bishop or knight. Auto-queen is an option.

How a game ends

• Checkmate wins: the king is attacked and has no way out.
• Resigning loses at once.
• Running out of time loses, unless your opponent has nothing left that could ever mate (a lone king, or a king and one minor piece against a bare king): then it is a draw.
• Stalemate, insufficient material, the same position three times, and fifty moves each without a capture or a pawn move are all draws. The last two end the game by themselves: there is nothing to claim.
• Players may agree a draw. In ranked games each player can offer a draw three times a game, with only one offer open at a time.

Ranked play: clocks, aborts and leaving

• Staked games are 3 min + 2 s, 5 min, 10 min, with the increment added after every move. There is no bullet for money: a phone on a weak signal should never lose a stake to the network.
• Each side's first move is untimed, but must come within 20 seconds or the game is aborted: nobody wins, nothing is rated and both stakes go back.
• The server runs both clocks. Network delay is measured and credited back move by move, up to a fair limit, so a slow connection costs you no thinking time and a lying one gains none.
• If you disconnect, the clock keeps running. A player who is gone for 60 seconds while it is their move loses the game.

Ranked play: stakes, ratings and fair play

• Each city is one stake. You are paired with a player in the same city and time control whose rating is within 100 points, widening to 250 while you wait.
• The winner takes the pot minus the fee. Every draw and every aborted game refunds both stakes in full, with no fee.
• Ratings use Glicko-2: a new rating moves quickly until the system is sure of it.
• Every move and its timing is stored, and anyone can replay a finished game move by move. Games are checked for engine use, and two players can meet at most 6 times a day for money.
• Practice games against the computer players are never staked, and computer players never sit at a staked game.