Everyone blunders. But players who keep blundering the same way, game after game, aren't just having bad luck. They have a specific pattern. BlackboxChess runs Stockfish across your game history to find exactly which type of error keeps showing up and how much it costs you.
It's easy to think of blunders as one-off lapses. You weren't paying attention for a moment. The clock was low. You missed a tactic you'd normally see. All true sometimes. But for most players, a specific type of blunder shows up far more often than others.
The player who keeps hanging pieces is usually hanging them in a specific kind of position, under a specific kind of pressure. The player who keeps losing won games usually has a specific breakdown point in the conversion phase. These are trainable patterns, not random mistakes.
BlackboxChess runs Stockfish across your last 10 to 100 games and classifies every significant error into recurring mistake categories across material loss, king safety, piece activity, pawn structure, and endgame technique.
The results are ranked by actual cost per occurrence, not just frequency. If you're wondering why you keep dropping games you should win, the answer is usually in the top one or two categories.
Hanging pieces is one of the most common top-ranked patterns in players below 1400. The analysis catches it through engine verification: a piece was undefended or moved into a position where it could be taken without adequate compensation, and the engine confirms the position was otherwise good enough to not justify the loss.
If hanging pieces is your pattern, the fix course includes positions from your own games where this happened — so you're training against the specific type of position that catches you, not generic "don't hang pieces" puzzles.
The free tier analyzes your last 10 games and shows your top blunder category. No account, no credit card. Most people recognize the pattern immediately once they see it named. The $10 full report covers 100 games with game examples and a targeted fix course.
"I actually consciously took your analysis' advice today for a game and got my rooks in the game quicker than I would. Led to me having more attacking pieces to create threats with, which led to my opponent blundering under pressure and resigning."
BlackboxChess user
"I can say that after trying, trusting and testing BlackboxChess, I am quite better for it and grateful. You've earned a serious fan of your work."
BlackboxChess user