New on Pro
Meet Ferz, your chess counsellor.
In chaturanga, the ferz stood beside the king and gave counsel. Ours sits beside your board in Learn, Practice and Analysis: ask anything about the position and Ferz answers in plain words, from Stockfish 19's own lines.
- Grounded. Every answer is built from Stockfish's lines for your exact position.
- Checked. Each move Ferz names is verified against the engine before you see it.
- Honest. A confidence score on every answer, with the reasons one tap away.
- Curious. When your question is unclear, Ferz asks back instead of guessing.
Practice · White to move · Italian Game
Not at all: d3 is a good move. Stockfish's top choice is c3, and it rates the two almost the same. Its line even plays d3 next: 4. c3 Nf6 5. d3 d6 6. O-O O-O, a quiet Giuoco Piano that stays about level.
How an answer is made
- 1Read the board
Ferz sees what you see: the position, the moves that led to it, Stockfish's top lines and the move you chose.
- 2Understand the question
It works out which move or line you mean: “c3”, “line 2”, “my move”, “the knight to g5”. If it can't tell, it asks.
- 3Ask Stockfish
Anything the lines don't cover, a move you're curious about or the opponent's threat, is searched on our server.
- 4Answer, checked
The answer is worded from those facts only. Every move it names is checked against the engine, and the confidence score says how sure it is.
The confidence score
Every answer carries a score from 0 to 100, and a tap shows why:
- Understood your question: how sure Ferz is about which move or line you meant.
- Stockfish behind it: the depth of the search. Practice and Learn positions are labelled by Stockfish 19 at full depth; in Analysis it depends on how long your engine ran.
- Claims checked: the share of moves and evaluations in the answer that the engine confirms. An answer naming a move Stockfish never gave is never shown as it was written.
Why not a chess-trained AI?
We looked at the open chess language models (ChessGPT, Chess-GPT, ChessSLM, Queen and others). Small ones predict moves but can play illegal ones and cannot explain; the ones that explain need large GPUs and still get variations wrong. So Ferz never guesses chess: Stockfish 19 decides, and the language model only puts the engine's verdict into words.
Ferz comes with Pro and Pro Max
Pro includes 100 questions a day and Pro Max 500, with your skill ratings, learning gaps and far more training. One-time passes, no auto-renewal.
Start free, then upgrade