Chess: Play Free Online Against the Computer

Chess: Play the Computer is our own free chess game, the classic board game with the full standard rules: castling on either side with all its conditions, en passant, promotion to a queen, rook, bishop or knight of your choice, check, checkmate and stalemate. Draws are automatic for threefold repetition, the fifty-move rule (50 moves each with no capture and no pawn move) and insufficient material. There is no chess clock, so you can take as long as you like over every move.

Play chess against the computer at four levels. Milo (Easy) looks one move ahead and slips up, but won't give the queen away for nothing. Nora (Medium) sees a few moves ahead and makes the odd small slip. Viktor (Hard) searches deep for up to 0.4 seconds a move, and Ada (Expert) thinks for up to about a second, as deep as it can. Pick White, Black or Random. Your side is always at the bottom, so the board turns round when you play Black. The computer varies its first moves and thinks in the background, so the board never freezes. For 2 player chess, play a friend on the same phone, tablet or computer: White sits at the bottom and the Flip button turns the board.

Tap a piece and dots show its legal moves, with rings on the squares where it can capture; then tap a square or drag the piece there. Tapping another of your pieces switches to it, and a switch in the menu hides the dots if you prefer a clean board. The last move is highlighted, a king in check glows red and coordinates run along the edges of the board. The move list uses standard algebraic notation (e4, Nf3, O-O, exd8=Q+), and next to each name you see the pieces that side has taken and its material lead, such as +3.

Undo is free and unlimited: against the computer it takes back your move and its reply, and in a two-player game it takes back the last move. Resign asks you to confirm first. A game in progress is saved in your browser, so you can close the page and continue later, and your games won, lost and drawn are recorded for each level.

Every day there are five chess puzzles, the same for everyone for the UTC day: two mate-in-one, two mate-in-two and one mate-in-three. They come from a collection of 2,020 positions that our own chess engine found in computer games, and each has exactly one winning first move, checked by a full search. After that first move, any move that still mates in time is accepted, and the defence always plays its most stubborn reply. A wrong move isn't played; it just costs points. Each checkmate puzzle is worth up to 200: 120 for solving it, less 30 for each wrong move (never below 30), plus up to 80 for speed (all 80 within 30 seconds, falling to nothing at three minutes). Showing the answer scores 0, so a day is worth up to 1000, and your total goes on the leaderboard once all five are done. The puzzle clock stops while the menu is open. Practice mode gives you unlimited puzzles from the same collection, by mate in 1, 2 or 3, and they don't count.

The only paid item is a hint for 10 gems. In a game it shows the move Expert would play: its squares glow and the move is named. In a puzzle it lights up the next move. Hints never change any score. Music and sound effects for moves, captures, castling, check, promotion and wins each have their own switch, and the game remembers your choice. Every piece and all the art is drawn in code, and all the sound is made in code. Chess: Play the Computer is free to play in your browser with no download or sign-up, in English, Japanese, Chinese and Spanish, on phones in portrait or landscape, tablets and computers, with touch or mouse.