what’sthisposition

Review any chess game, move by move.

Enter a Chess.com or Lichess username, a game link or a PGN. Stockfish labels every move from Brilliant to Blunder and explains why. Free, in your browser.

Review a whole game
Try a classic:
Add to Chrome

The Chrome extension reviews your Chess.com games right where you play them.

Or analyse a single position

A screenshot from a game, a FEN or a board you set up. It shows the threats, weaknesses and plans for both sides on the board, checked by Stockfish.

Every move gets a label

Each move is compared with Stockfish's best in winning chances, on Lichess's win-probability curve. The same rules apply to every game, from your blitz games to world championships. How each label is decided

Review it without leaving Chess.com

The free extension reviews a finished Chess.com game right where you played it: both players' accuracy and every move counted, from Brilliant to Blunder. One more click opens the whole review here, already done.

  1. Finish a game on Chess.com, or open one of yours.
  2. Click the extension's button and press Analyze. Stockfish reviews the game on your computer.
  3. See every move explained opens it here, step by step.
Add to Chrome, it's free

For Chrome, Edge, Brave and other Chromium browsers on a computer. It only reviews finished games, and collects nothing. More about the extension

The extension's card on Chess.com after a game: both players' accuracy, the opening, and how many moves of each kind each player made

How a strong player reads a board

One position, read four ways. Every line below is worked out live from the board by the same code that reads your positions.

01

What's under attack right now?

  • White has 1 checking move: Bxh7+.
02

Where are the weaknesses?

  • White's pawn on d4 is hit by 2 Black pieces and defended by 1.
  • White still has 1 minor piece at home (c1) on move 10.
  • Black's bishop on e7 is Black's worst piece: 2 safe squares and nothing to attack. Improving it is a plan in itself.
  • Black still has 1 minor piece at home (c8) on move 10.
03

What's working for each side?

  • White's knight on c3 is White's most active piece: 5 safe squares, 8 controlled.
  • White has more space: 12 to 9 behind the pawns in the centre.
  • Black's knight on f6 is Black's most active piece: 6 safe squares, 8 controlled.
  • Black's queen on d8 presses down the half-open d-file.
04

What could happen next?

  • White rook f1 → e1, onto the half-open e-file. Conditions hold now.
  • White pawn break d5, hitting e6. Needs: d5 is covered at least as often as it's attacked (1 v 3).
  • Black knight c6 → b4 → d5, an outpost. Needs: White can't trade off the knight right away.

What each idea looks like on the board

Once you've seen these a few times, you start spotting them in your own games before the engine points them out.

Threats

Pieces under attack flash red. Forks and skewers draw their lines.

Domination

Every square a piece controls floods in its side's colour.

Passed pawns

The runway to promotion lights up, square by square.

Holes

Squares no pawn can ever defend again open up as pits.

Pawn chains

Chains link up, and the base, the point to strike, is targeted.

King danger

The squares around an exposed king heat up with every attacker.

Open files

Files without pawns become highways, and linked rooks pulse along them.

Space

Territory behind each side's pawns fills in: who has room to breathe?

Questions

What people ask before they paste their first game.

Is it really free?

Yes. There is no account, no daily limit and nothing to unlock. Stockfish runs on your own device, so a review costs nothing to serve. The code is open source (GPL-3.0).

How do I review my Chess.com games?

Type your Chess.com username and pick a game from your last three months. You can also paste the PGN (Share, then PGN, on Chess.com), or add the Chrome extension and review a game right on its Chess.com page.

Can I review Lichess games or a PGN file?

Yes. Enter a Lichess username or paste a game link. Any PGN works too: paste it, or drop the .pgn file on the page. Files with several games let you pick one.

How are moves labelled?

Each move is compared with Stockfish's best by how much of your winning chances it gives away: under 2% is Excellent, under 5% Good, then Inaccuracy, Mistake, and Blunder at 20% or more. Brilliant needs a real sacrifice that is also the best move; Great is the only move that holds.

How close is the accuracy to Chess.com's?

The accuracy score is fitted on games Chess.com reviewed, and usually lands within about 3 to 4 points of Chess.com's number for the same game.

Is my game uploaded anywhere?

No. Games, positions and photos stay in your browser. A username is only used to fetch your public games from Chess.com or Lichess. Visits are counted anonymously, without cookies.

Can it explain a single position or a screenshot?

Yes. Drop a screenshot or photo of a board, paste a FEN or set up the pieces by hand. It shows the threats, weaknesses and plans for both sides on the board, checked by Stockfish.

Bring the game you lost last night.

Type your Chess.com username or paste the PGN, then step through it move by move.

Add to Chrome