Blunder Zero : Chess Coach

Stop repeating the same mistakes.

Blunder Zero is a personal chess coach built around the games that matter most: your own.

Import your games, discover the mistakes that keep costing you points, and turn them into targeted training. Instead of endless random puzzles, Blunder Zero helps you learn from your own blunders, missed tactics, and recurring patterns.

Powered by on device Stockfish analysis, Blunder Zero works fast, privately, and even offline.

WHY BLUNDER ZERO?

Most chess apps show you what went wrong in a single game.

Blunder Zero shows you what keeps going wrong across all of your games, then helps you fix it.

Review every move with clear explanations.
Find recurring mistakes and weak habits.
Train on positions from your own games.
Build lasting improvement instead of short term puzzle ratings.

KEY FEATURES

♟ Personal Game Review
Import PGN games or connect Lichess and get a complete move by move breakdown.

🎯 Train From Your Own Mistakes
Convert your blunders, mistakes, and missed tactics into personalized training drills.

🧠 Human Like Insight with Maia
See what players at your level would likely play, alongside Stockfish's best move.

🎓 Real Time Chess Coach
Get clear feedback while you play and learn to spot mistakes before they happen.

🚨 Blunder Detection
Identify the critical moments that changed the game and understand exactly why.

📈 Recurring Mistake Tracking
Discover the patterns that repeatedly appear across your games and focus your training where it matters most.

📚 Opening Repertoire Tracking
See your most played openings, where you deviate, and which lines deserve attention.

🔎 Master Games Lookup
Compare your positions with stronger players and learn from real games.

⚡ On Device Stockfish Analysis
Fast, private, offline first analysis directly on your phone.

📊 Background Analysis
Analyze multiple games while continuing to review and train.

ACCURACY YOU CAN VERIFY

We independently validated our accuracy scoring against Lichess. Across 800 player games, Blunder Zero's accuracy closely matched Lichess with a Pearson correlation of 0.978 and scores within 3 points on 85% of games.

MADE FOR PLAYERS WHO WANT TO IMPROVE

Whether you are a casual player, club player, or competitive online player, Blunder Zero helps you:

• Find recurring mistakes
• Build stronger habits
• Improve from your own games
• Stop losing the same way twice

HOW IT WORKS

1. Import a PGN game or connect Lichess
2. Review every move with clear coach feedback
3. Train the mistakes that matter most
4. Watch your weaknesses disappear over time

Stop repeating the same mistakes.
Start training on the games you actually play.

Recent changes:
Bring your history with you
Save a backup file of your games, analysis and practice history, then restore it after reinstalling or moving to a new phone. No account needed.

Clearer, more reliable cloud backup
Backup status now reflects confirmed cloud saves, and restore messages are clearer when there is nothing to restore.

Ready for Android 16