Rocket Chess

What is Rocket Chess?

Rocket Chess is a complete chess game that runs entirely in your browser. Play against the computer at four levels, from Cadet, which makes human-sized mistakes, to Admiral, which searches several moves ahead, or pass the screen to a friend. Tap a piece to see every legal move, drag or tap to play it, and the board highlights the last move and any check.

All the rules are in: castling, en passant, promotion with a piece chooser, checkmate, stalemate, the fifty-move rule, threefold repetition and insufficient material. Undo takes back your last move (and the computer's reply), Hint asks the engine for a suggestion, and the game is saved so a closed tab costs you nothing.

How to play Rocket Chess

1. Choose your opponent, level and colour at the top, then tap New game.
2. Tap a piece: dots mark the squares it can move to, rings mark captures. Tap a target or drag the piece there.
3. When a pawn reaches the last rank, pick the piece it becomes.
4. The status line shows whose move it is and announces check; the move list records the game in standard notation.
5. Use Undo to take back a move, Hint for a suggestion, and Flip to turn the board around.

Rocket Chess tips and strategy

• Control the centre early with pawns, bring out knights and bishops, then castle.
• Before each move, look at what your opponent's last move attacks.
• Trade pieces when you're ahead and avoid trades when you're behind.
• Against the higher levels, play slowly and avoid leaving pieces undefended; the engine punishes hanging pieces instantly.
• Level 1 and 2 play with deliberate randomness so beginners get real chances to win.

The four computer levels

Cadet looks one move ahead and picks among reasonable moves at random, so it blunders like a beginner. Pilot searches two moves deep with a little randomness. Commander looks three moves ahead with no randomness and punishes mistakes. Admiral searches up to five moves ahead within a few seconds per move. The engine runs in a background thread, so the page stays responsive while it thinks.

Rules handled automatically

Castling is offered only when it's legal (king and rook unmoved, nothing in between, no square in check along the way). En passant appears as a capture target the move after an enemy pawn double-steps past you. Draws are declared for stalemate, threefold repetition, the fifty-move rule and insufficient material.

Rocket Chess FAQ