Fun
Chess
A complete game of chess in your browser. Play the built-in engine at five levels or pass the device to a friend.
Your move
No moves yet.
Drag a piece or tap it and then tap a highlighted square. Dots mark legal moves; rings mark captures. The computer thinks in a background thread on your device, and no moves are uploaded.
Play and explore in your browser. No account needed.
Frequently asked questions
How strong is the computer?
Beginner looks one move ahead and chooses randomly among moves that are close in value, so it often misses tactics. Casual and Intermediate search two and three moves ahead with less randomness. Advanced and Expert search for about one and three and a half seconds, typically looking eight to twelve moves ahead on a modern laptop. Expert is a firm test for club players, but it is not a grandmaster-level engine.
Does every chess rule work here?
Yes. Castling, including the rule that the king cannot castle out of, through or into check, is supported, as are en passant and promotion to a queen, rook, bishop or knight. Checkmate and stalemate are detected automatically. The game is also drawn after threefold repetition, fifty moves without a capture or pawn move, or when neither side has enough material to checkmate.
Can I play against a friend?
Yes, in Two players mode both sides move on the same screen. Flip board turns the view around for the player with black. It is a pass-and-play game on one phone, tablet or computer; it does not create an online room or connect two devices.
How do the clocks work?
Choose 3 + 2, 5, 10 or 15 + 10 minutes. The clock starts after White's first move and runs for the side to move, adding any increment after each move. A player who runs out of time loses, unless the opponent has too little material to checkmate, in which case the game is a draw. Undo does not return used time.
What are PGN and FEN?
PGN is the standard text format for a whole game, with move lists in algebraic notation that analysis boards and chess databases can import. FEN describes a single position in one line: the pieces, the side to move, castling rights and the en passant square. Copy FEN saves the current position, and Load FEN starts a game from any legal position you paste.
Is anything uploaded or saved?
No. The rules and the engine run in your browser, with the computer's search in a background thread so the board stays responsive. Moves are not sent to a server and there is no account. Reloading the page starts a new game, so copy the PGN first if you want to keep it.
About this tool
This page is a complete chess game that runs in the browser. Every legal move is generated from the position, including castling, en passant and all four promotion choices. Moves are recorded in standard algebraic notation, and the game ends by itself on checkmate, stalemate, threefold repetition, the fifty-move rule or insufficient material. Legal-move dots, the last-move highlight and a red glow on a king in check help while you are learning.
The computer opponent was written for this site. It searches with alpha-beta pruning and iterative deepening, orders moves so that promising captures and earlier cutoffs are tried first, and continues checking captures at the end of each line to avoid simple blunders. Its evaluation counts material and adds bonuses for piece placement, mobility, passed pawns, open files for rooks and a pawn shield around the king. The search runs in a Web Worker, so the board still responds while the computer is thinking.
The five levels suit different players. Beginner and Casual make deliberate, human-like inaccuracies and are good for learning how pieces move and for young players. Intermediate is steadier and punishes pieces left undefended. Advanced and Expert play without deliberate mistakes and vary only the first few moves, so games do not repeat the same opening. Expert gets the longest thinking time and is a sensible sparring partner for improving players.
Two-player mode turns a phone, tablet or laptop into a board for two people sitting together, with optional clocks for blitz or rapid games. Export the finished game as PGN to review it in any chess analysis program, or copy a FEN to share a position. The game is kept only in this tab, so reloading the page starts a new board.