One game hides it. Thirty show it.
After a loss you remember the one terrible move. What you don't notice is that it was the third knight fork you missed this month, or that every game with the Sicilian was lost before move fifteen. Weaknesses aren't moments. They're patterns, and a pattern needs many games to show up.
That's also why looking through your games by hand rarely works. You'd need to go through thirty games with an engine, mark every costly move, and keep a tally. A computer can do that tally for you. You only need to know what to ask it.
Read every game, mark every swing.
Stockfish looks at every position you reached and asks one question: did your move throw away real winning chances? The moves that did get a second, deeper look, to find out why. Scroll to watch a scan run on an example set of games.
Two kinds of blind spot.
Every tactical slip is one of two things, and they need different fixes. Keep them apart in your head and in your training.
MissedYour chance, not taken
- ✕You had a fork, a pin, a mate
- ✕You played a quiet move instead
- ✕The chance was gone a move later
- ✕Fix: look for your forcing moves
Walked intoTheir chance, handed over
- ✓Your move left something loose
- ✓Your opponent had the tactic
- ✓Usually one move deep
- ✓Fix: check their replies first
Where your openings go wrong.
Tactics are half the picture. The other half is the opening: some lines leave you a pawn down or a tempo behind by move twelve, every time, and the rest of the game is spent catching up. To find them, group your games by opening and side, and for each group look at three numbers.
- The record. Wins, draws and losses in that opening.
- Out of the opening. The engine's verdict after move twelve, from your side. A minus sign that keeps coming back is the warning.
- Slips. Moves in the first twelve that cost a fifth of your winning chances or more.
Example: openings, ranked by cost
After move 12, from your sideNotice what the example shows: the Italian wins with White, but with Black the Two Knights Defence goes wrong at the same moment game after game. That isn't bad luck or a tactical blind spot. It's one opening move you were never taught.
Start with move one.
The broadest view is the simplest: with White, how do your games go after each first move you play? With Black, after each first move you meet? If you score 60% against 1.e4 and 35% against 1.d4, you know which half of your repertoire to work on before you look at a single variation.
What to do with what you find.
Pick one pattern
The top of the list, not the whole list. Forks first, if forks are what you miss.
Solve it ten times
Ten puzzles of that exact pattern, every day for a week, until you see it before you calculate it.
Fix the costly opening
Learn the line where it goes wrong — with the reason for each move — and drill it from memory.
Play, then read again
After twenty more games, scan again. The pattern you trained should shrink; a new one takes the top spot.
Or let Blind Spots do the tally.
Everything above is what Blind Spots does with your username. Pick chess.com or Lichess and how many games to read. Stockfish runs in your browser and reads every position. Then the report shows:
- your number-one tactical pattern, with every moment from your games on the board,
- the other patterns ranked beneath it, each with a set of real puzzles to train,
- your openings ranked by what they cost you, with the costliest move in each and the move that held,
- how your games go after each first move, as White and as Black,
- and for each opening, the course that covers it.
It's honest about what it can't do. It reads tactics and opening moves. It won't tell you why you lose long endgames, and a weakness that shows up in one game out of thirty is noise, not a pattern.
Questions, answered.
How do I find my weaknesses in chess?
Look at many games at once rather than one. Have an engine mark every move that lost real winning chances, then group those moments: by tactical pattern (forks, pins, back-rank mates) and by opening. The groups that keep coming back are your weaknesses.
How many games do I need to analyse?
Twenty to fifty recent games is enough for patterns to show. Fewer than that and one bad day can look like a weakness; much older games may show problems you have already fixed.
What is the difference between a missed tactic and one I walked into?
A missed tactic is one you had and didn't play. One you walked into is a move of yours that handed your opponent a tactic. The fix is different: the first is about looking for your chances, the second about checking your opponent's replies.
How can I tell which opening is costing me games?
Group your games by opening and side, then compare three things: your results, the engine's verdict on the position after move twelve, and how many real mistakes you made in those first moves. An opening that leaves you worse out of the opening, game after game, is the one to study.
What should I do once I know my weaknesses?
Train one pattern at a time. Solve puzzles of the tactic you miss most, and for the opening that goes wrong, learn the line properly: the moves and the reason for each, then drill it until you can play it from memory.
