The backward pawn, and the hole in front of it

The pawn is not really the target. The square in front of it is, and that is the square a knight moves into and never leaves.

Tell No friendly pawn can ever defend it
Where you meet it Sicilian, Benoni, King's Indian

A backward pawn is the straggler in its group. The pawns beside it have gone past it, so none of them can ever drop back to defend it, and the square in front of it is covered by the enemy, so it cannot advance to join them either. Nothing about the pawn itself makes it backward. Its neighbours did that.

It becomes a real problem when the file it sits on is half open, because then it is not just a pawn that needs a piece to look after it, it is a pawn that enemy rooks can line up against without moving a pawn of their own. And it comes with a second weakness attached: the square in front of it, which no pawn of yours can ever contest.

The Sicilian d6 pawn

Black has just played 5...e5, hitting the knight. It gains time and space, and it fixes d6 for the rest of the game: Black has no c-pawn any more and the e-pawn has gone past. The dots are the seven squares the attacked knight can go to, and the fight from here is about the amber ones.

This is a bargain Black makes on purpose, in the Najdorf and the Boleslavsky and half the Open Sicilian. The pawn on d6 is permanently sickly and d5 is permanently White's. In exchange Black gets the centre under control, a free hand on the queenside and the sort of position where the second player plays for a win. Whole careers have been built on each side of that deal.

Attacking one: take the square first

Beginners attack the pawn. Strong players take the square. In the position above White is not really trying to win the d6 pawn, White is trying to land a knight on d5, and the standard method is to trade off the pieces that guard the square rather than to hit the pawn: Bg5, exchange on f6, and the knight arrives. A knight on d5 there is an outpost that no pawn can question.

The pawn comes second. Rooks double on the half-open file behind it, the queen sits behind them, and every black piece that has to stay home and defend is a piece missing from the other wing. Above all, keep it fixed: the moment the defender gets the freeing advance in, the weakness and the square both vanish.

Defending one

You have three cures and they are all worth knowing. Play the break anyway, at the right moment and sometimes at the cost of a pawn, because a backward pawn that advances and gets traded is no longer a backward pawn. Trade the pawn off some other way, usually by exchanging it for something on the file. Or make it irrelevant by generating enough activity elsewhere that nobody has time to organise a siege.

What you do not do is sit still and defend it with pieces forever. That is the losing plan, because the defender runs out of useful moves long before the attacker runs out of ways to add pressure.

Half-open file plus backward pawn equals a plan. Without the file it is often just an untidy pawn.
The square in front of it is the real prize. See weak square.
As the attacker, fix it first. As the defender, get the break in.
Trading the right minor pieces decides it. Whoever controls the square in front wins the argument.

Questions people ask

Is a backward pawn always weak?

Not always. It needs two things to become a real target: a half-open file for enemy rooks, and no way of ever advancing. If you can play the freeing break in a few moves it is a temporary inconvenience. Half the Sicilian is built on accepting a backward d-pawn for good reasons, so count what you were paid before you call it a weakness.

How do you get rid of a backward pawn?

Advance it. That is the only clean cure, and it usually needs preparation: pieces on the square in front, an exchange or two to remove a defender of that square, and sometimes a pawn offered to make the break work. Failing that, exchange the pawn for an enemy pawn on an adjacent file, or accept it and get counterplay somewhere the attacker cannot ignore.

Backward pawn sits under Pawn structure in the reference. Nearby: