The chess blunder you keep repeating

You look at the position for a few seconds.

You check things.

Nothing seems wrong.

You play the move, and you know instantly.

It is the most common question in chess forums, and it rarely gets an answer: why was it invisible for those seconds and obvious half a second later? The usual explanations are carelessness, tiredness, playing too fast. Those all exist. None of them explain the timing.

When you sit down to a puzzle, the hardest question has already been answered for you. You know something is there. All that is left is finding it.

In a game nobody answers it. Every single move, you decide for yourself whether this position even needs a second look. Dan Heisman, who has taught club players for decades, builds his book Is Your Move Safe? around exactly that gap. Solving puzzles trains you to find things. Noticing that there is something to find is a different skill, and it is the one that decides your games.

A blunder is one move that makes your position a lot worse in one go. Lichess works out a chance of winning for every position, and a move counts as a blunder when it takes fifteen points off that chance. Chess.com draws the line in a different place and folds your rating into it, so the same move can be judged differently for two players. Either way the mark tells you what a move cost, not how easy it was to see.

Why you see a blunder one second after you played it

Because that is when the question changes.

Wolfe and colleagues sat people in front of X-ray pictures of luggage and asked them one thing: is there a weapon in this bag? In one run, half the bags held one. In another, only one bag in fifty did. When weapons were common, one bag in five was missed. When they were rare, almost half were missed.

The pictures were no harder to read, and the people were no worse at telling a knife from a pair of scissors. What changed was how much it took before they said yes. When you almost never find anything, you stop expecting to.

The same thing is going on at the board. Your answer to "is anything wrong here" is no, and it is right almost every time, which is exactly why you give it so quickly. Missing the piece was never an eyesight problem. It was an answer you gave without noticing you gave it.

Playing the move takes that answer out of your hands. There is nothing left to decide, so you look at the position the way you would look at someone else's, and there it is.

It shows up wherever people look for things. Evans and colleagues slipped a hundred mammograms into nine months of ordinary hospital work, and later showed the same doctors the same hundred cases as a study, where everyone knew a lot of them were positive. In the working day they missed thirty percent. In the set, twelve.

You did not miss it. You said no without thinking about it.

Playing the move your opponent had against you

While your opponent is thinking, most players wait.

The habit worth building is the other one. Use their turn to think for them. What are they threatening? What does the move you are about to play hand them? Asking that, every time, is most of what board vision is.

In Chessou that question is an exercise, and it is called "Their Best Move". A position comes back out of a game you played, from your own perspective, exactly as you saw it at the time. Your move plays out, and then you are asked for the reply it allowed. The move you are looking for is the best one your opponent had, so it comes back to you even if nobody played it at the time.

You are not asked for a better move. You are asked what your move gave away, and then shown what you could have played instead.

In a game you are sitting behind your own pieces and nobody asks you what your opponent could do next. You have to ask it yourself, every move. Chessou puts that same question in front of you over and over, on positions you really had, until you start asking it yourself in the middle of a game, while there is still something you can do about it.

How that question starts showing up on its own

Sticking with it is the hard part.

The usual answer is to try harder to remember. Ask the question every move, no exceptions. Every blunder checklist on every chess forum is that answer written down, and the people who wrote those checklists are still dropping pieces a month later. A checklist only works while you are paying attention, and paying attention is the thing that slips.

Stronger players are not paying better attention than you. They are not asking the question at all any more. They just see it. Junta Ikeda, writing about what to do while your opponent is thinking, turns the usual claim around.

You do not start seeing it because you got stronger. You get stronger because you started seeing it without trying.

Seeing it without trying comes the same way anything else does, by doing it over and over. But not any practice will get you there. It has to be the same question, in the same kind of position, again and again.

Doing the same thing for months is where most people stop, because nobody keeps at something that dull just because it is good for them. What keeps people going is being rewarded for it, and the reward does not even have to be worth anything. Denny and colleagues put practice questions online for their students. Answering them was voluntary and counted towards nothing, so anyone could ignore the whole thing. One group got a small badge on screen every time they answered one. The other group got nothing. The badge was worth nothing either, just a picture. The students collecting them did far more of the work.

Chessou is designed around that finding. Training earns you XP, ranks and a streak. A harder position is worth more, and getting one wrong still pays, just less. The repetition is what makes the question automatic, and repetition needs a reason to keep going.

How to practise this on your own

You do not have to take a website's word for any of this. Mark Dvoretsky, one of the best known trainers the game has had, wrote a whole book about it.

He describes the skill as the ability to think not only for yourself, but also for your opponent, to put yourself in his place, and he is blunt about where you can pick it up. Not in your games. Training it in a tournament game is difficult, he writes, so you set the position up somewhere quiet instead and work on it there. The book gives you four chapters of positions to practise on, and it starts easy.

Jacob Aagaard teaches the same thing as one of three questions to ask before you choose a move, and the third one is what your opponent is planning.

But those positions are not yours. They come from other people's games, picked because they show the idea well. The moves you hand your own opponents are not in any book.

In Chessou those are the positions you train on. The exercises are built from your own games, so the moves you handed your opponents come back to you. And they keep coming back: the same position turns up again a few days later, then after a longer gap, each time just before you would have forgotten it.

What happens in Chessou

Your games come in on their own. You enter your Lichess or Chess.com username once and they keep arriving. Anything you played elsewhere, over the board included, goes in as a PGN. Every move is then checked against 79 hand built patterns.

The strongest move you did not play becomes a puzzle. Same position, same side, your turn again.

The moves that let something through turn into an exercise of their own. Your move plays out again and you are asked for the reply it allowed, on the board as you had it.

A pattern that keeps coming back becomes a drill on that one pattern, built from every game it showed up in.

Everything you train comes back later, in the set waiting for you the next day.

Your openings turn into a repertoire built from the lines you really play, with the ones that keep costing you points coloured in. Where a line leaks, you swap it for a better one and train the new branch.

Play a game in Chessou and the training is waiting when it ends. The board takes you back through up to three moments of the game you just played. It is optional, and it takes the place of starting another game straight away.

Reports read back what the system found across all your games, so you can see which patterns are getting rarer.

Not every game gives you something. When there is nothing worth stopping at, Chessou says so instead of inventing an exercise for you.

Try it on your own games

Enter your Lichess or Chess.com username and your games are imported and analysed before you pay anything. Every account starts with one week free, everything included. Plans are on the pricing page. There is also a piece on what your game review can't tell you, and a side by side with Chess.com if that is where you play.