AI chess move analysis, explained in plain words
Explain is a button that sits under the commentary for a move. Press it and the coach tells you, in plain words, why that move was good or bad. When the move was a mistake, the answer names the move to play instead and says what that move does. It works on your own moves and on your opponent's.
The same button appears in the AI Coach trainers, such as Pattern Drill, and in Learn from Mistakes.
What an answer tells you
An engine tells you that a move was a mistake. It does not tell you why. Explain is the move explanation that fills that gap, and what it says depends on how the move was graded.
- A good move. What the move does: what it attacks or wins, what it rescues, what threat it takes away. If it was the engine's first choice, the answer does not go looking for a better one. If another move was worth about the same, the answer does not present yours as a slip.
- An inaccuracy, mistake or blunder. What goes wrong after it, usually the reply that punishes it and what that reply wins. Then the move to play instead and what it does: the check it gives, the piece it attacks, the material it wins.
- A missed chance. What was there, what it would have won, and what the move you played did instead.
- A new threat. When a move creates a threat that was not there before, the answer says what it threatens.
- A tactical pattern. When a fork, pin or other pattern is at work, the answer names it.
How the answers read
Answers are written to you, in the second person. Your moves are yours and your opponent's moves are theirs, so an explanation of your opponent's blunder reads as their mistake, not yours.
Moves are described in words rather than notation, and there is no engine vocabulary: no evaluations read aloud, no centipawns, no talk of depth. Each answer is about the position on the board and nothing else. It does not guess at plans it cannot see, and it does not end with general advice for future games.
The length follows the position. A quiet move can get a single sentence. A move that drops a piece gets the full reason. The answer also adds to the commentary already on screen instead of repeating it.
Chess terms in an answer, such as fork, outpost or deflection, carry a short definition you can open by hovering over the word or tapping it. If you step away from a move and come back to it, the answer you already read is shown again straight away.
Opening moves
A move that is still opening theory has no mistake to explain. Explain answers those from written commentary on the opening for that position: what the move is and the line it belongs to. Where no commentary exists for that exact position, it says the move is still theory and names the opening.
Where you can use Explain
Game Report. Game Report analyses your game with Stockfish 18 running in your browser and grades every move. Explain sits under the commentary for each move, so you can ask about any of them, including your opponent's.
AI Coach trainers. In the trainers, such as Pattern Drill, Explain appears once you have moved. After a wrong move it says why the move fails and what to play instead. After you solve a position it says why your move works. After the answer is shown it says what the correct move does. It does not appear before you move: that is what hints are for.
Learn from Mistakes. Learn from Mistakes turns the mistakes from your own games into positions to solve again. Explain there talks about the move you actually played in that game and the move that would have been better.
Frequently asked questions
What does Explain do?
It explains a single chess move in plain words: why it was good or bad, what it threatens, and when it was a mistake, which move to play instead and what that move does.
Can it explain my opponent's moves?
Yes. In Game Report you can press Explain on any move in the game. An opponent's move is described as theirs, so their blunder reads as their mistake and not yours.
What happens when I press Explain on an opening move?
A move that is still opening theory is answered from written commentary on that opening, which says what the move is and the line it belongs to.
Where can I use Explain?
Under the commentary for each move in Game Report, in the AI Coach trainers once you have made your move, and in Learn from Mistakes.
Will Explain give away a puzzle before I move?
No. In the trainers Explain only appears after you have moved or the answer has been shown. Before that, the hints are there to help.
Is Explain the same as Game Report?
No. Game Report analyses the whole game and grades every move. Explain answers one move at a time, when you ask, and says in words why that move earned its grade.