A chess blunder trainer with Anki-style spaced repetition. BlunderBoards analyzes your games with Stockfish, finds your blunders, and drills you on the best response until you stop making the same mistakes.
- Export your games as PGN from chess.com (or any other source).
- Copy the PGN files into the
game history/folder. - Open
index.htmlin your browser. - Click Analyze Games to detect blunders from your PGN files.
- Use Save to File after analysis to embed the results so you don't have to re-analyze on next load.
- Stockfish engine analysis to detect blunders (≥150 centipawn evaluation drop)
- SM-2 spaced repetition: correctly solved blunders appear less often
- Hint system: highlights the piece to move (penalizes the card interval)
- History navigation: step back through previous puzzles to compare positions
- Pre-analysis: save analyzed blunders directly into the HTML file for instant load
Chess piece SVGs are in the pieces-basic-svg/ folder (Wikipedia CC-BY-SA, Uray M. János).