How Chessiro reviews your games, what the AI coach actually does, and how training is built from the mistakes you keep making.
Chessiro is a chess improvement platform built around your own games. You import a game, get a full Stockfish review with every mistake explained in plain English by an AI coach, and then train on puzzles built from the positions you actually misplayed. The idea is simple: playing more games repeats your mistakes, reviewing them removes them.
Game review is free and unlimited — there is no one-review-per-day cap. A free account also includes AI coach previews, two Smart Shuffle training sessions per week, and a limited number of custom puzzles. Paid Plus and Pro plans raise the AI coach and training limits. No card is required to start.
You can paste a PGN and get a Stockfish review without creating an account. Signing in is what lets Chessiro remember your games, build a skill profile across them, and turn your recurring mistakes into training.
Yes. You can connect your Chess.com or Lichess account to import games directly, or paste a PGN from any source — including over-the-board games you have transcribed. Games you play against Chessiro's bots can be reviewed the same way.
Stockfish 18, running in your browser. Analysis is done locally rather than queued on a server, which is part of why reviews can be unlimited and free.
Engine analysis of every move, move classifications from best to blunder, an accuracy score with an estimated rating, an evaluation graph, a phase-by-phase breakdown of your opening, middlegame and endgame, time-usage analysis, and an opening explorer. Each turning point comes with a plain-English explanation of what the move missed.
They are severity bands for how much a move cost you, measured in win probability rather than raw centipawns. An inaccuracy is a small slip, a mistake meaningfully damages your position, and a blunder is a serious error that usually decides the outcome. Chessiro also marks the good end of the scale, so you can see the strong moves you found, not only the errors.
Yes. Every review groups its findings into what needs work and what you nailed. Chessiro detects patterns across the game — missed forks, pins you did not see, hanging pieces, back-rank weaknesses, king safety, endgame technique, trade decisions and more — and shows the strengths alongside the weaknesses, each backed by the specific move where it happened.
Accuracy is derived from how much win probability each of your moves gave away, then calibrated against a rating-balanced sample so the number is comparable to what you would see on other platforms. It is a summary, not a verdict — the classifications and explanations tell you far more than the percentage does.
The coach reads the engine's analysis of your actual position and explains it in plain English: what the threat was, what the better move accomplished, and what you should have been looking at. You can ask follow-up questions about any move, and it can play out what-if lines to show you why an idea does or does not work.
It helps with the part most players skip. An engine tells you a move was wrong; it does not tell you why you missed it or what to do about it. Chessiro names the concept behind each mistake, tracks which concepts keep recurring across your games, and turns them into training positions — so the explanation becomes practice rather than trivia.
24 languages, including Spanish, French, German, Portuguese, Hindi, Arabic, Japanese, Korean, Mandarin, Russian and Turkish. Every one of them is voiced, so the coach can read its explanation aloud as you move through the game.
Yes. Chess terms in the coach's explanations link to a glossary, so if it mentions a skewer, a passed pawn or zugzwang you can read the definition without leaving the position.
Smart Shuffle is a training session built from your skill profile rather than a generic puzzle set. Chessiro analyzes your games to map strengths and weaknesses across openings, tactics, calculation, strategy, conversion, endgames and time management, then assembles a session that mixes puzzles rebuilt from your own mistakes, drills on your weakest themes, and puzzles you have solved before resurfacing so the pattern sticks.
A standard puzzle set drills tactics chosen for everyone. Puzzles from your own games drill the ones you demonstrably missed, in positions you have already seen from the inside. Chessiro rebuilds them from the exact moment your evaluation dropped, so you get a second attempt at the decision you actually got wrong.
Yes. Your skill profile updates as you play and train, weighted toward recent games so it reflects your current level rather than mistakes you fixed months ago. Each session picks a focus theme, and if you are still struggling with it the next session returns to it; once you are handling it, the focus moves on.
Smart Dash is the same personalized training on a 120-second clock, for practising pattern recognition under time pressure. Untimed sessions give you three lives and a running streak, with a summary afterwards showing where the puzzles came from and how you did.
They are built on Maia, a neural network trained to predict human moves rather than to find the objectively best one. That means they attack, defend and blunder the way real players at a given level do, instead of playing perfectly and then throwing a piece away on purpose. There are ten strength levels from 250 to 3000, plus an adaptive mode that tracks your own rating.
Yes. Online games and friend challenges run through a connected Lichess account, at rapid and classical time controls. You can also play offline pass-and-play on a single device, and every game — online, bot or pass-and-play — can go straight into game review afterwards.
Yes, and that is the point of playing here. A bot game or an online game flows directly into the same review pipeline as an imported one, so a casual game still tells you what to work on.
Players who want to know what to work on next. It is built for beginner through advanced club players — the range where nearly every lost game contains one clear moment where it turned, and where finding that moment is worth more than another hour of blitz.
Because reviewing your games is the single most useful thing an improving player can do, and we do not think that belongs behind a paywall. Engine analysis runs in your browser, which keeps it cheap enough to give away. The paid plans cover the AI coaching and personalized training built on top of it.
A small team of chess players who wanted an analysis tool that says what to improve rather than showing an evaluation bar moving up and down. You can read more about why we started on our blog.
Free game review
Paste a PGN or import from Chess.com and Lichess, and get a free Stockfish review with every mistake explained in plain English — no account needed to try it.
