Deflection and decoy

A game on lichess.org, 2014. The white rook on b1 looks up the file at the black rook on b6, but it cannot take it yet: the pawn on c7 defends the rook, and after the exchange White would win nothing. Exactly one pawn is in the way. If it disappeared somewhere, the rook on b6 would be hanging.

The pawn will not leave by itself. But it can be made to: if a white piece lands with check on a square the pawn attacks, the pawn will have to take it. Find such a move.

The knight in this puzzle was bait. It could win nothing by itself, but it forced the pawn off its post. And the pawn had only one job: guarding the rook. That is how deflection works, and it is the first half of the chapter.

Two techniques, one idea

In the last few chapters we looked for double attacks: the fork, the pin, the skewer, the discovered attack. Often such a blow is almost ready, but one enemy piece spoils it. It defends what you want to take, or covers the square you want to reach, or stands where you would rather it did not. The techniques in this chapter rearrange the opponent's pieces by force.

Deflection drives an enemy piece away from where it is needed. It was defending a piece, a square or a line; it is forced to take a sacrifice, to get out of check or to escape a threat, and the defence is gone.

Decoy does the opposite: it lures an enemy piece to where you need it. Most often that is the king or the queen: a sacrifice brings them onto a square where a fork, a pin or mate is waiting.

Both ideas rest on the same thing: the opponent is obliged to reply with a particular move. To a check, they must move, block or capture. To a queen sacrifice, they must take the queen, or they will be a queen down. If the opponent has only one reply, you know where their piece will be after it, and you can prepare the blow in advance. Deflection looks at where the piece leaves from. Decoy looks at where it arrives. Often it is the same move seen from two sides.

You have already met both techniques, just without names. In chapter 11 a white rook gave itself up on c6: the black rook took it and landed on a square where the bishop attacked it and the king at once, with check. That was a decoy into a fork. And in the first puzzle of chapter 12 White defended the queen with a knight without noticing that the knight was pinned: there the pin did the deflection's work by itself, the defender was in place but could not defend.

The difference from what awaits you in the next chapter is simple too. There the defender is captured, or caught out because it has two jobs at once. Here it is neither captured nor caught out, but lured away.

Deflection

Deflection starts with a question: who is in the way? Look at the blow you would like to strike and find the enemy piece that spoils it. Then find a move that piece is obliged to answer: a check it has to block, a sacrifice it has to take, a threat it has to escape. If there is such a move, the defender leaves and the blow gets through.

There are four ways to drive a defender off, and you will meet all of them in this chapter. A sacrifice: you put a piece where precisely the defender has to take it, like the knight on d6 in the first puzzle. A check: the defender blocks it, or the king itself steps out of check and abandons what it was defending. A threat: an attack on the defender by a cheaper piece, after which it does not pay to stay put. And an exchange: you trade off a piece the defender has to recapture, and it ends up on another square. The more forcing the move, the more reliable the deflection. A check is the most forcing of all, because it allows the fewest replies.

It is driven off with a check. If you check the king along a diagonal that only the rook can block, the rook will block it, but it will leave the eighth rank.

Deflection does not always need a sacrifice. Sometimes a check the defender must step away from is enough, especially when the defender is the king itself. The king defends the pieces around it, but it moves out of check, and what it was defending is left alone.

A piece can defend a square or a line as well as another piece. A rook on a file defends everything on it. Deflect the rook, and the file is left without an owner. Often the deflecting move also clears the way for one of your own pieces: that happened in the first puzzle, where the knight left b5 and opened the file for the rook. Here is another such case.

The rook on d3 did two jobs here with one move. It drove the defender off the c-file and cleared a line for its own queen. The second idea is called line clearance, and it is a technique in its own right. Strong moves often combine several ideas at once, which is why the names of techniques are not boxes into which every move must be sorted, but words that help you see them.

In the endgame, deflection most often helps a pawn through to queen. An enemy rook stands in front of the passed pawn and guards the promotion square. Attack it with your rook so that it can neither leave the square nor take the pawn, and the defender is gone. In the diagram below White plays Rc8: the rook lands next to the rook on b8 and attacks it. If …Rxc8, then bxc8=Q. If the rook leaves b8, the pawn goes through by itself. Black cannot take the pawn on b7: the pawn on a6 defends it.

Decoy

With a decoy the question is different: where would you like the enemy piece to stand? The king, on a square where it can be mated or forked. The queen, on a square where a knight or a pawn can take it. Then look for a sacrifice the opponent is obliged to take with exactly that piece. If the sacrifice is made on the fatal square, it brings the piece there by itself.

The king is lured most often, and most often for mate. A king sheltered by pawns is safe as long as it stays behind them. A sacrifice drags it one square forward or sideways, and there nothing shields it any more: your pieces cover the squares around it, while its own pawns take away its retreat. A queen sacrifice for mate looks beautiful, but behind it lies simple arithmetic: if mate is unavoidable after the capture, the price of the queen does not matter.

The king is lured not only into mate. If the king lands on a square where it can be checked with a fork, that wins too. The queen is lured even more often: it is worth more than anything else and falls for forks by knights and pawns. The scheme is this: you give up a piece on a square the enemy queen attacks and your knight or pawn already has in its sights. The queen takes, and the next move is a fork.

To see such squares, it helps to know the geometry of forks from chapter 11. A knight hits the king and the queen at once if they stand at its "distance": on squares of the same colour, two or three squares apart. A pawn hits two pieces standing a square apart on the same rank in front of it. If the enemy king is well placed for a fork and the queen is not, look for a sacrifice on the square the queen would have to reach to walk into it.

A pawn fork pays even better than a knight's: the pawn is worth one point, so any piece it takes is pure profit. In the next puzzle the pawn fork is half ready: the king already stands next to the striking square, and a rook sacrifice brings the queen there. See where the white queen ends up if it takes the rook.

A decoy goes well with the discovered check from the last chapter. A sacrifice puts the king on a line where your rook or bishop stands behind one of your pieces. The front piece's next move uncovers check and takes something along the way.

How to look for them

Both techniques need a sacrifice or at least a check, and so they are easy to miss: there seems to be no reason to give anything away. It helps to make a habit of asking two things in every sharp position.

1. What is in my way? Find a blow that almost works: a mate, a fork, a capture. See which enemy piece spoils it. If there is only one, look for a move that drives it away.
2. Where do I need their piece? Find a square where the enemy king or queen would perish: under a fork, under a discovered check, in a mating net. If you have a sacrifice on that square that the opponent is obliged to take, the blow is ready.

Then calculate to the end, and calculate the opponent's replies, not just the one you like. A sacrifice is a move after which you have less material. If the opponent can decline it, or step out of check onto a different square, or take with the wrong piece, the calculation collapses. The players who made the moves in the puzzles above had to check every reply: in the puzzle with the rook on c8 the king could go to h7, and then White simply took the queen on c3; in the puzzle on h3 the king could decline the queen, and then came mate on g2.

The price of the sacrifice also has to be weighed against what you get. Mate pays for any sacrifice. A fork of king and queen pays for a rook. But if a decoy wins only a pawn and you gave a knight for it, it is a mistake, however pretty it looks. The piece values from chapter 8 still apply here.

Finally, remember that the opponent has a choice too. They can decline a deflecting sacrifice if taking it is worse than losing what the defender protects. Then your sacrifice is left hanging, and you lose a piece for nothing. That is why the best deflections and decoys come with check or with a threat of mate: the opponent has no right to refuse.

Defending against these techniques is harder than against a fork: the threat is not on the board yet, it appears after the sacrifice. A simple rule helps. If one of your pieces is the only defender of an important square or piece, that is a weakness, even when everything is defended. Add a second defender in advance, and deflection loses its point. And a king with no free square is a ready target for a decoy and a back-rank mate. A free square for the king, the "luft" that the chapter on mating patterns will cover in detail, protects against that as well.

What's next

Deflection drives a defender away by force. But sometimes the defender can simply be taken, and then whatever it was defending is left hanging. And sometimes there is one defender with two jobs, and it cannot do both at once. That is removing the defender and overloading, the subject of the next chapter.