# Blunders

> Blunders is a chess improvement platform that turns the moves you actually lose to into a personal training plan. Link a chess account (or paste a PGN) and Blunders syncs your games every day, runs full engine analysis on each one, and surfaces the exact moves that cost you the point.

Blunders is built for adult improvers (rated roughly 800–2200) who play online and want their study time to track their actual mistakes instead of generic problem sets. It is not a beginner tutorial site and does not teach chess from scratch.

## What it does

- **Daily game sync.** Connect a Chess.com or Lichess account once. Each night Blunders pulls your fresh games and runs Stockfish analysis on every move. PGN upload is supported as a manual alternative.
- **Blunder detection.** Every move is graded against the engine's evaluation. Blunders, mistakes, inaccuracies, and recoverable errors are tagged automatically.
- **Pattern clustering.** Mistakes are grouped by tactical or positional theme — forks, pins, back-rank, mishandled R+P endgames, opening principle violations, and so on — so you can see *why* your rating leaks, not just *which game* leaked it.
- **Puzzles built from your own losses.** Spaced-repetition tactics drills are generated from your top weakness clusters. The puzzle bank also includes thousands of themed positions for general training.
- **Opening repertoire.** Tracks the lines you actually play, sorted by win rate, with ECO classification and lessons for openings you're soft in.
- **AI coach.** A coaching agent with full context on your game history can answer "why was this move bad", "what was the threat", or "what should I study next."
- **Progress dashboards.** Rating, blunders-per-game, and puzzle accuracy trends over 30/90/365 days.

## Who it's for

- Players who plateau because their study is disconnected from their real weaknesses.
- Players who want focused 10–20 minute training sessions instead of grinding generic puzzles.
- Players who already have games online (Chess.com / Lichess) and want them analyzed automatically.

## Key URLs

- Marketing site / sign-up: https://blunders.ai/
- Free opening guides index (all guides, for White and Black): https://blunders.ai/openings
- Free opening guide — Caro-Kann Defense (main lines, variations, traps on an interactive board): https://blunders.ai/openings/caro-kann
- Free opening guide — London System (main lines, variations, traps on an interactive board): https://blunders.ai/openings/london-system
- Free opening guide — Italian Game (main lines, variations, traps on an interactive board): https://blunders.ai/openings/italian-game
- Free opening guide — Sicilian Defense (main lines, variations, traps on an interactive board): https://blunders.ai/openings/sicilian-defense
- Free opening guide — French Defense (main lines, variations, traps on an interactive board): https://blunders.ai/openings/french-defense
- Free opening guide — Queen's Gambit (main lines, variations, traps on an interactive board): https://blunders.ai/openings/queens-gambit
- Free opening guide — Scandinavian Defense (main lines, variations, traps on an interactive board): https://blunders.ai/openings/scandinavian-defense
- Free opening guide — Vienna Game (main lines, variations, traps on an interactive board): https://blunders.ai/openings/vienna-game
- Free opening guide — Scotch Game (main lines, variations, traps on an interactive board): https://blunders.ai/openings/scotch-game
- Free opening guide — Ruy Lopez (main lines, variations, traps on an interactive board): https://blunders.ai/openings/ruy-lopez
- Free opening guide — King's Indian Defense (main lines, variations, traps on an interactive board): https://blunders.ai/openings/kings-indian-defense
- Free opening guide — English Opening (main lines, variations, traps on an interactive board): https://blunders.ai/openings/english-opening
- Free opening guide — Slav Defense (main lines, variations, traps on an interactive board): https://blunders.ai/openings/slav-defense
- Free opening guide — Pirc Defense (main lines, variations, traps on an interactive board): https://blunders.ai/openings/pirc-defense
- Free opening guide — Dutch Defense (main lines, variations, traps on an interactive board): https://blunders.ai/openings/dutch-defense
- Terms: https://blunders.ai/terms
- Privacy: https://blunders.ai/privacy
- Contact: https://blunders.ai/contact

## Status

Currently in beta. Freemium: a free account includes the daily puzzle, puzzle
training, community features, and the opening guides — no credit card
required. Automatic game sync, engine analysis, and AI coaching are part of
the paid Pro subscription.