The in-between move and blunders

A game on lichess.org, 2014. Black to move. The white queen on h5 is attacked by the knight on f6, and Black can take it. But the black queen on d6 is attacked too: the pawn on e5 hits it.

If Black takes the queen at once, White takes the queen on d6 back, and it is just a trade. Black wants more: to win the white queen and keep their own. There is one move for that, after which the white queen still has nowhere to go.

Taking the queen was on the board the whole time. Black put it off by one move: with check they took their own queen away from the pawn, and White had no time left to save theirs.

What an in-between move is

When the opponent takes one of your pieces, the answer seems obvious: take back. Most of the time that is right. But sometimes you can slip in another move first, one the opponent must answer. After it the capture is still possible, and your position has improved.

An in-between move is a move played instead of the expected one. The opponent captures; you do not take back at once, but first give check, take something else or create a threat. Chess players often use the German word "zwischenzug", which means exactly "in-between move".

An in-between move works only if the opponent is obliged to answer it. The most reliable such move is a check: it cannot be brushed aside. A queen capture and a threat of mate are almost as reliable. If the opponent can ignore your move, they will take something themselves, and you will lose more than you gained.

And one more condition: whatever you meant to take must stay where it is. Ask yourself whether the opponent, while answering your in-between move, can also save their piece. If their answer to the check is a move with the very piece you wanted to take, or a move that defends it, the in-between move achieved nothing. If they are busy with their king, the piece is still yours.

The in-between move has a dark side. You can not only play one but also miss one by the opponent. You calculate: I take, they take, I take. But instead of "they take" the opponent gives a check of their own, and the calculation falls apart. That kind of mistake is a common road to a blunder, a gross mistake that loses a piece or misses a mate. Blunders are the second half of the chapter.

Check first

Let us start with an endgame position. The black rook on e5 stands next to the white king on d4, and nothing defends it. It can be taken. But look at what happens after the capture.

The rook on c7 is badly placed: if the king goes to e5, the bishop will hit the king and, through it, the rook. So before the capture, the rook has to be moved. And moved with check, so that Black has no time to save their own rook.

An in-between move often looks just like this: a threatened piece steps out of danger with check. The opponent spends a move protecting the king, and you collect what was lying on the board. Here is a harder example: White can take the bishop, but there is a stronger move.

Look at why the bishop on f3 stayed put. White gave two checks in a row, and both times Black had to block. The bishop had no time to leave, and the pawn on g2 stood next to it the whole time. The more forcing moves in a row, the more you manage to collect.

The same technique works when your queen is under attack. You want to take something, but the queen is en prise, and the opponent will take it in reply. Then look for a queen move with check after which your capture is still on the board.

Sometimes an in-between check saves a piece and also leaves the opponent's pieces worse placed. In the last puzzle of the section, a check drives the king onto the file your rook is hitting.

The opponent's in-between move

Now look at the same technique from the other side. Every time you calculate an exchange, you assume the opponent will take back. Usually they do. But before you start an exchange, ask yourself: what if they do not take back, but give a check first or attack one of my pieces?

The position with the rook on e5 shows what is at stake. Had White taken the rook with the king, they would have walked into the bishop's skewer. That is exactly the opponent's move that wrecks a calculation: you expect them to accept the loss, and they answer with a check. In chapter 11 we saw the same thing with the fork: the opponent answers with a check of their own, moves one piece away, and the fork comes up empty. And in the previous chapter the opponent's move seemed forced, but it was forced only because they had no check of their own.

It helps to calculate an exchange as a chain of questions. I take; what can the opponent do? Not only take back, but everything else too: checks, captures of more valuable pieces, attacks on my queen. If there is such a move, I calculate it as well. Usually the branch is short and ends quickly: the opponent has nothing better than a plain recapture. But the one position where the branch does not end is the one that decides the game.

The check is simple. Before you capture, find all the checks and all the captures the opponent will have after your move. Usually there are few of them, one or two. If one of them hits your piece with check or attacks two at once, your capture needs a second look. The check takes a few seconds and saves whole games.

A special case is a piece that cannot be saved anyway. If your knight is attacked and has nowhere to go, do not hand it over for nothing: perhaps it can take something on its way out. The opponent knows this too. When you trap one of their pieces, check what it can take before it dies. Such a piece is called a desperado, a Spanish word chess players use for a piece that sells its life as dearly as it can.

Blunders

A blunder is a mistake you can see at a glance: a piece left en prise, a missed mate in one, a move after which the opponent immediately takes something. Everyone blunders, beginners and strong players alike. The difference is how often. And almost every blunder could have been seen, had the player looked at the board the right way.

Most blunders come from haste and from looking only at your own plan. You have an attack in mind, you are calculating it, and the opponent's last move slips past you. Moments when the game seems won are dangerous too: attention relaxes, and a spare piece suddenly finds itself under attack. And another dangerous moment is an unexpected move by the opponent. If they have given up a piece, first check whether it is a trap, like the traps in chapter 10.

The most common blunders all work the same way. A piece goes to a square the opponent attacks, and nothing defends it. A check is especially treacherous: it feels as if a check is always good, since the opponent must answer it. But if the checking piece is itself attacked, the opponent will answer the check in the simplest way: by taking it. In the next three puzzles the opponent has just made a mistake. Find what they left.

The second common blunder is subtler. The piece put nothing en prise itself, but it left its post and abandoned what it was defending. You read about this in the chapter on overloading: every piece has duties, and when you move it, you take them away from it.

To avoid this kind of blunder, ask yourself before the move: what was this piece defending while it stood here? If the answer is "nothing", move it calmly. If it was defending something, check whether that something still has another defender.

There is also the opposite mistake: the defender seems to be in place but cannot defend. A piece pinned to the king may not leave the line of the pin, which means it can recapture only along that line. Most often that means it cannot recapture at all. You saw this in the chapter on the pin. When you count defenders, cross out the pinned ones.

The last exercise is the trainer from chapter 8, at its hardest level. In each position one piece is hanging, and the others only look defenceless. Find the one you can take for free.

The check before a move

Strong players blunder less, and not only because they see the board better. They have trained themselves to run a short check before every move, even when short of time. Here it is in three steps.

1. What did the opponent do? Look at their last move. What does that piece attack now? What has it stopped defending? Is there a threat to capture, fork or mate?
2. What checks, captures and threats do I have? Before playing a quiet move, go through them. Sometimes one of them is an in-between move stronger than what you meant to play.
3. What happens after my move? Put the piece on its new square in your mind. Does the opponent attack it? What has it stopped defending? Which checks and captures will the opponent have?

At first the check feels slow. After a few dozen games it becomes a habit, and you stop noticing it, the way you stop noticing that you look both ways when crossing a road. In fast games a single glance is enough: just do not make your move until you are sure none of your pieces is hanging.

Do not try to calculate everything in every position. The job of the check is modest: not to play a bad move. You look for the best move when there are checks, captures and threats on the board. In a quiet position a good move that puts nothing en prise is enough. That is how strong players play too: lots of calm, sensible moves, and precise calculation where it is needed.

A good habit after the game as well: find your blunders in it. The engine analysis on this site marks them for you. Look at each one and ask at which step of the check you would have caught it. The answer is usually the same, and you will learn which of the three questions you skip most often.

What's next

Many puzzles in this chapter and the earlier ones ended in mate. Mates repeat themselves: the same arrangements of pieces turn up in thousands of games, and many of them have names. Recognise the pattern, and you can find the mate in seconds. That is the subject of the next chapter.