Free tool, no account
Chess Game Analyzer: See the Tactics You Missed
Updated
Type a Lichess or Chess.com username. We run Stockfish over the 5 most recent rated games, find the moments where a tactic was on the board and the move played was not it, and name each one: fork, pin, skewer, mate. Nothing to install, nothing to sign up for.
Analyze my games
Your missed tactics land here
Up to 6 of them, each on its board, with the move you played and the name of what was there instead.
What the analyzer shows you
The tactic, named
Not an eval swing: a fork, a pin, a skewer, a back rank mate. The name is only printed where our tagger has earned it on the Lichess puzzle database; otherwise it says "a tactic" rather than guess.
Missed or allowed
A missed tactic was yours to play. An allowed one is the move that handed your opponent theirs. Both cost games, and they are trained differently.
The exact moment
The board before your move, the move you played, and a link to the game: on Lichess it opens at that move, on Chess.com at the start with the move number given.
How it works
Enter your username
Lichess or Chess.com. We read your 5 most recent rated blitz, rapid or classical games from the site's public API; nothing is stored about you.
Stockfish reads every move
For each of your moves (the first 40 of each game) the engine compares what you played with what was there. A big enough gap becomes a candidate, and only a candidate whose winning move is the ONLY winning move survives a deeper search.
Each find gets a name
The winning line is tagged by its motif: the fork, the pin, the mate pattern. You see the position and the name; the answer stays hidden, so you can still find it yourself.
Why an engine eval alone isn't enough
Every game review shows you a number that drops: +1.2, then -2.5, a red question mark. It tells you THAT something went wrong. It does not tell you what you should have seen, and "-3.7" is not something you can recognise in your next game.
A pattern is. Players who stop missing forks did not memorise evaluations; they learned to see two pieces a knight can attack from the same square. So the analyzer turns the drop into the pattern behind it, and only where the pattern is real: a positional slide or a slow squeeze is left out, because it is not a tactic and calling it one would teach the wrong lesson.
And it keeps only the positions with one answer. If two moves won, the moment was not a puzzle, it was a choice, and replaying it would mark you wrong for a move that also wins.
Replay them until you find them
A free account scans 20 games in total across your linked accounts (once, not per month), keeps every miss, and serves each one back as a puzzle you replay until the move is yours. Pro scans with no cap.
Questions
Is the chess game analyzer free?
Yes, and without an account. It reads your last 5 games. With a free account the scan reads 20 games in total across your linked accounts, a lifetime allowance rather than a monthly one, and turns every miss into a puzzle you replay; Pro removes the cap.
Which games does it analyze?
Your 5 most recent rated games on the site you pick: blitz, rapid and classical on Lichess, every rated time control but bullet on Chess.com. Bullet is left out because a missed tactic with two seconds on the clock is a clock problem, not a vision one.
Do you store my games or my username?
No account is created and nothing about you is written down. The result is cached for a while against your newest game, so a second look is instant; it is not linked to you.
How is this different from Lichess or Chess.com game review?
Those show the engine's opinion of every move. This shows only the moments a tactic was on the board, names it, and leaves the answer for you to find. It is a list of patterns to train, not an evaluation graph.
Why did it find nothing?
Because there was nothing clear to find in those 5 games, or because the miss was positional rather than tactical. The analyzer is strict on purpose: a position with two winning moves, or a gain the engine only sees deep in the line, is not shown.