Brain games and quizzes011 games / 2720 quizzes

Boards and strategy

Chess

Play a full game against the computer at the level that suits you, or solve the daily puzzle: the same position for everyone, every day.

Levels
100, 200, 400, 800, 1200, 1500, 1800, 2100, 2400, Max
Daily
Puzzle
Scored by
Win, draw or loss
Today
Daily puzzle
Setting up the board

Rules

  1. 1.White moves first, then the players alternate. Each side starts with a king, a queen, two rooks, two bishops, two knights and eight pawns.
  2. 2.You win by checkmate: the enemy king is attacked and has no legal way out. You may never make a move that leaves your own king in check.
  3. 3.Castling, en passant and promotion all work as in over the board play. A pawn that reaches the far rank becomes a queen, rook, bishop or knight of your choice.
  4. 4.The game is drawn by stalemate (no legal move, not in check), threefold repetition of a position, fifty moves by each side with no capture or pawn move, or when neither side has enough material to mate.
  5. 5.In a casual game you may take back moves. A strict game allows none. You can resign at any time.
  6. 6.The daily puzzle starts with your opponent's move. Find the best reply, then keep finding the best move until the line ends. Any move that gives checkmate counts.

How to play

Controls
InputAction
Click or tap a piece, then a squareMove the piece; dots mark the legal squares
Drag and dropMove a piece in one motion
Arrow keys, then Enter or SpaceChoose a square, pick up a piece and put it down
EscapeCancel the selected piece or the promotion choice
Take backUndo your last move and the reply (casual games)
Flip boardSee the position from the other side
H or HintShow the engine's best move (casual games)
Left and right arrows, Home, EndStep through the review after a game
  • 100: Random moves that leave pieces hanging: anyone can win
  • 200: Mostly random, grabs a loose piece now and then
  • 400: A new player: knows the moves, often leaves pieces hanging
  • 800: Plays natural moves but misses most tactics
  • 1200: Sees simple threats, slips in long fights
  • 1500: A solid club player
  • 1800: A strong club player, tactically alert
  • 2100: Expert strength
  • 2400: Master strength
  • Max: Stockfish at full strength in your browser

Strategy

  • In the opening, bring out your knights and bishops, castle early and fight for the centre squares d4, d5, e4 and e5.
  • Before every move ask three questions: what is my opponent threatening, what did their last move change, and is any of my pieces loose?
  • Checks, captures and threats: look at forcing moves first, for both sides. Most tactics start with one of them.
  • Trade pieces when you are ahead in material, and avoid trades when you are behind.
  • In the endgame the king is a strong piece. Bring it towards the centre and push passed pawns.
  • Lost to a level? Copy the PGN and replay the game slowly, looking for the move where things went wrong.

Questions

How accurate are the opponent ratings?
They are approximate ratings, roughly comparable to online blitz ratings. From 1500 up the engine limits its own strength to the rating you choose. The 100 and 200 bots play almost at random, so anyone can win. Below 1500, 400, 800 and 1200 are our own calibration: a shallow search that picks among sensible moves, so the computer makes human sized mistakes rather than random ones. Max is the engine at full strength.
What does "you played like a 1750" mean?
After the game the engine checks every move. Your performance rating is a rough estimate from how much winning chance your moves gave away on average, blended with the result against your opponent's rating. One game says little, so it comes with a range, and short games are not rated.
How do hints work?
In a casual game, press Hint or H on your move and the engine shows its best move as an arrow. Hints are counted, and your record notes wins without them. Strict games and the daily puzzle have no hints.
Does the computer run on a server?
No. The engine downloads once when you start a game, about 1.8 MB, and then thinks on your own device. Nothing about your game is sent anywhere.
How does the daily chess puzzle work?
Everyone gets the same puzzle each UTC day. Monday is the easiest and the puzzles get harder through the week, with the toughest on Sunday. Solve it, wrong tries and all, to keep your streak going.
What is PGN?
Portable Game Notation is the standard text format for chess games. Copy it after a game and paste it into any chess program to replay or analyse your moves.
Can I challenge a friend?
Yes. After a game, copy the challenge link: it opens the same level and colour, and after a win it carries your move count for your friend to beat.

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