Blunderproof (Free Chess Review & Coach)

Free game review for Chess.com and Lichess, with a coach that explains every move in plain words. Runs on your computer.

Free game review for Chess.com and Lichess, as well as a coach that explains every move in plain words. DESCRIPTION Blunderproof is a free chess coach that reviews your games, finds your patterns, builds you a plan, and gives you a drill for every step of it. REVIEW YOUR GAMES • Connect your Chess.com or Lichess username (no password needed) and pick a game. • Every move is graded as Brilliant, Best, Excellent, Good, Book, Inaccuracy, Mistake, Miss or Blunder. • The coach explains what each move does, what was better and why, what your opponent was threatening, and what happens next. It also names the other moves that were fine, and says what a trade does to the pawns. • Still confused? "I still don't get it" explains what's wrong with your move and why the better move is better, then plays it out on the board. • "Show best move" plays the engine's choice on the board and tells you why it's best. • Move the pieces yourself to explore your own what-if lines. • A "Review in Blunderproof" button appears on your finished games on Chess.com and Lichess, and the review starts the moment you open it. YOUR PLAN • My patterns reads your games and puts together a short plan, with the exact things to work on, most useful first, each with the numbers behind it. • Every step has a Start button that opens the drill for it. • Results by color, time control and opponent strength, your best and worst openings, how your games are decided (one big mistake or bit by bit, and in which phase), accuracy by game phase, and the wins that slipped away. • Progress shows whether the training is working, with your rating, played like, accuracy and puzzle rating over time, a calendar of your Daily workouts, and a weekly check-in (this week against last week). • Session guard, a small reminder after a game when your plan says it's time to stop (never during a game). TRAIN • Daily gives you a short workout each day (puzzles, threats and one more drill), with a streak. What you learned in Openings and Lessons comes back here for a quick review, spaced out so it sticks. • Puzzles has 178,000 rated puzzles from the Lichess database, in 31 themes (hanging pieces, forks, pins, mates and more), matched to your puzzle rating. • Threats puts you on move while your opponent threatens something. Show their threat, then stop it. • Puzzle Rush gives you 3 minutes, 5 minutes or survival. How many can you solve? • Openings teaches any opening one line at a time. You see two moves and why each is played, then play the line back from memory. 100 of the most played openings come with a card (the idea, your plan, a memory hook and the trap to know). It starts with the openings you actually play. • Winning positions lets you finish off positions you were winning in your own games, plus the basic mates and endings, against a strong bot. • Visualize trains seeing ahead with moves in your head, blind puzzles, and quick square drills. • Puzzles from your own mistakes, which come back until you know them. • Lessons give short theory on checkmate patterns, endgames and tactics. You try each idea on the board, practice it in positions from real games, and finish with one rule to remember. A mixed quiz checks that you can spot which idea applies. • Guess the move lets you play through famous games as the winner and see how your moves compare. PLAY BOTS THAT FEEL HUMAN • Bots from 400 to 2200, measured on real Chess.com and Lichess games, that choose moves like real players and think longer on the hard moves. A Move now button when you don't want to wait, or Auto to have the bot reply right away every move. • Blunder check stops you before a move that throws away material, so you can look again. • Every time control, pause, premoves, and looking back through the game while you play. FAIR PLAY Blunderproof never works during a game in progress. The review button and the session guard only appear after a game is over, and live games are refused. PRIVATE No account, no tracking, no ads. The Stockfish chess engine (Stockfish 18 for reviews) runs on your own computer. The only thing Blunderproof sends anywhere is your username, to Chess.com or Lichess, to download your public games. Light and dark mode, Book and Club styles, 12 boards (wood, walnut and marble among them) and 16 piece sets. Four coach voices (Plain, Casual, Short and Scholarly). Beginner mode with friendlier labels and bigger text. Works with screen readers and the keyboard. Save all your data to a file and load it back. Menus and buttons in 51 languages (the coaching explanations are in English for now). Free. The chess engine is Stockfish (GPLv3). Puzzles and opening lines come from Lichess (CC0). Blunderproof is an independent project and is not affiliated with Chess.com or Lichess.