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The library

Remember what your games already taught you.

Written for players between 1000 and 2000: the mistakes that keep happening, how to see them a move early, and how to make them stop. Every page is short, has a quiz, and points at the real games where the pattern shows up, including yours.

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What this library is, who it is for, and the one idea everything else rests on: you do not need another engine, you need to remember.

  1. How this library works A short guide to reading, quizzing, and then repairing the same mistake in your own games. Ten minutes, and you will know how to use every page here. 3 min read · 3-question quiz
  2. Why you keep making the same mistake Humans forget. Players repeat mistakes because they do not remember making them. What that means for how you review a game, and a ten-minute routine that works. 3 min read · 3-question quiz

Mistakes that keep happening

The ways club games are actually lost, each measured across thousands of real games. How to see them a move early.

  1. Hanging pieces The single most common way club games are lost is leaving a piece where it can be taken for free. Here is the counting habit that makes it stop, and why it fails under pressure. 4 min read · 3-question quiz
  2. Loose pieces and forks A piece that is undefended is a target even when nothing attacks it yet. Forks and double attacks are how the target gets hit. How to see the geometry a move early. 3 min read · 3-question quiz
  3. Pins and skewers A pinned piece is not really there. A skewer is a pin the other way round. Both win material in club games every day, and both are visible one move before they happen. 4 min read · 3-question quiz
  4. Removing the defender A piece is only as safe as the piece guarding it. Take the guard, chase it away, or make it do two jobs, and the thing behind it falls. This is the tactic hiding inside most club-game blunders. 5 min read · 3-question quiz
  5. Overloaded pieces A defender doing two jobs is doing neither. Find the piece that is guarding two things at once, ask it for both, and one of them is free. This is what happened in most of the games where you counted correctly and still lost material. 6 min read · 3-question quiz
  6. Discovered attacks One piece steps out of the way and the piece behind it attacks. You were watching the piece that moved. The one that takes your queen was standing still the whole time. 7 min read · 3-question quiz
  7. Back rank and mating nets Walking into mate is not a beginner's mistake. It happens to 1800s who are winning and stop looking at their own king. The two shapes to know, and the one pawn move that prevents most of them. 4 min read · 3-question quiz
  8. The missed win The engine's most humbling tag is the winning move you did not play. It is almost never a long calculation. It is a check, a capture, or a quiet move you did not look at because your own idea was in the way. 4 min read · 3-question quiz
  9. Dropping pawns A pawn is a small thing until the endgame, when it is the whole game. Where pawns actually get lost in club chess, and why "it is only a pawn" is the most expensive sentence in the game. 3 min read · 3-question quiz

Turning good positions into wins

Being better is not the same as winning. What to do when the engine already likes you.

  1. Converting a winning position Being better is not the same as winning. The engine's tag for throwing away a won game is one of the most common at every level, and it has one cause: the guard drops the moment you are ahead. 4 min read · 3-question quiz
  2. When to trade Every trade changes the game more than most moves. Six rules that decide almost every trade at club level, and the one that players between 1200 and 1800 get wrong most. 3 min read · 3-question quiz
  3. King safety Castle early, keep the pawns in front of your king where they are, and know the three moments when that rule is wrong. Most club attacks work because the defender broke one of these. 4 min read · 3-question quiz

Openings without memorizing

Enough opening knowledge to reach a playable middlegame every time, built from the games you already play.

  1. Principles that survive move ten You do not need to memorize openings to reach a playable middlegame every game. You need six principles and the discipline to follow them when the opponent does something you have never seen. 4 min read · 3-question quiz
  2. A repertoire from your own games The openings you should study are the ones you already play. How to find them in your own history, choose one plan per structure, and stop forgetting how to play against the French. 4 min read · 3-question quiz

Endgames that decide games

A short list of positions to know cold. They come up more often than anything you will memorize in the opening.

  1. King and pawn essentials Two ideas decide nearly every king and pawn ending at club level, the opposition and the square of the pawn. Know them cold and you will win endings your opponents think are drawn, and hold the ones they think are won. 3 min read · 3-question quiz
  2. Rook endgame essentials Rook endings are the most common endings in chess and the ones club players know least. Four ideas cover most of them: the active rook, the rook behind the passed pawn, the Lucena bridge, and the Philidor third rank. 4 min read · 3-question quiz

How to think at the board

The blunder check, candidate moves, the clock, and what to do after a bad loss.

  1. The blunder check A single question, asked in the same words before every move, removes most of the mistakes in this library. What the question is, why players stop asking it, and how to make it automatic. 4 min read · 3-question quiz
  2. The clock and tilt The same player makes the same mistake three times as often with thirty seconds left, and five times as often after a painful loss. What the data says about time and mood, and what to do about each. 4 min read · 3-question quiz

The apps inside the library

Repair your mistakes The site finds the moves that cost you, puts you back in the position, and asks again later until it sticks. Try it on your games No account needed. Your Chess.com or Lichess username, your last games, your first repair in a minute. Pattern statistics How often each mistake happens across thousands of analyzed games, by rating band and speed.