Why You Need Computer Analysis
If you want to improve at chess, playing alone isn't enough. You need to know why you lost. Was it a tactical blunder? A positional misunderstanding? Or did you miss a forced checkmate?
Professional players have used engines like Stockfish for years. However, many amateur players believe they need expensive premium subscriptions to access these tools. This is false. Stockfish is open-source, and you can access world-class analysis completely for free.
How to Get Your Game PGN
To analyze a game, you first need its record, usually in PGN (Portable Game Notation) format.
- Lichess: Go to your game, click the "Share" tab, and copy the "PGN" text.
- Chess.com: Click the "Share" icon (or "Download" button) on your game and select PGN.
- OTB (Over-the-Board): You can type the moves manually into an analysis board.
Using Free Stockfish Tools
Once you have your PGN, you don't need to pay. You can use free platforms like Plychess.com.
Sites like Plychess run Stockfish directly in your browser using WebAssembly. This means:
- Privacy: Your game data isn't sent to a server; it's processed on your device.
- Speed: Instant feedback without network lag.
- Cost: 100% Free. No "1 game per day" limits.
Simply navigate to the Analysis Board, paste your PGN, and toggle the engine.
Interpreting Evaluation (+/-)
Stockfish gives you a number, known as the evaluation (eval). Understanding this is key:
- +1.00: White is leading by the equivalent of 1 pawn.
- -3.50: Black is winning (minus means Black) by about a minor piece (Bishop/Knight).
- 0.00: The position is dead equal.
- #M5: Mate in 5 moves (forced win).
Don't panic over small shifts like 0.2 to 0.4. Focus on large swings (e.g., +0.5 dropping to -2.0), which indicate a blunder.
Finding Blunders & Missed Wins
When analyzing, don't just look at the engine's top line. Look for where the graph spikes.
The Golden Rule of Analysis: If you made a move and the evaluation dropped by more than 1.0, you missed something critical. Pause the engine. Don't look at the solution immediately. Try to find the tactic you missed yourself. This active recall strengthens your chess memory.
The "Guess the Move" Method
Passive watching is weak. Active participation is strong.
Use the Play vs Stockfish feature to re-play your game starting from the critical mistake. Can you convert the winning position this time? Or can you defend the lost position better than you did in the game?
Conclusion
You do not need a paid membership to analyze like a Grandmaster. Tools like Plychess put the power of Stockfish 16+ directly in your hands for free. Start reviewing every serious game you play, and you will see your rating skyrocket.