Isolated pawn

We call isolated pawn the pawn that has no pawns on adjacent files to protect it or support it's advance.In Diagram 1  both sides have an isolated e-pawn:

                                    Diagram 1

While in diagram 2 Black has 2 isolated pawns (c6 and a7) and white none.

                            Diagram 2

 The first impression you might have is that the isolated pawn is a clear weakness since it demands constant protection by pieces but that is far from true.The isolated pawn can be a liability but can be an asset too.

     In diagram 1 we have symmetrical isolated pawns and the activity of the pieces wil actually decide which pawn is a weaknsess and which is not.In  diagram 2 though only black has isolated pawns so how can we evaluate the position?

      First it is important to say that the isolated pawn at a7 is not considered a weakness since white has not a way to exert any pressure on it and black can easily protect it in any case.We usually consider weakness  the isolated pawn that is on an open file as in that case the side that plays against the isolated pawn can create a very strong pressure against it by doubling rooks on isolated pawn's file.

In Diagram 3 we can see a typical attack against isolated d-pawn.

                                            Diagram 3

It is obvious now why that kind of pressure can only be exerted in isolated pawns on open files.

    The general principle is that isolated pawn becomes more of a weakness as the pieces become less.An old principle says that "with 4 pieces for each side isolated pawn is an asset , with 3 the position is even , with 2 the isolated pawn is a weakness".Although that principle is far from correct(in diagram 3 we have 4 pieces for each side but the isolated pawn is a weakness and a very serious one) it does depict a significant truth:The less the pieces the more the weakness of the isolated pawn.

    We already have our first conclusion:

    "Isolated pawn is strong at the middlegame and weak as the game goes to the endgame"

The next games demonstrate why the isolated pawn can be an asset in middlegame.The attacking chances offered to the side with the isolated pawn more than compensate it's weakness.The attacks often are brutal and fast and even World Champions have problem defending against them.

                                              Game 1

That is the reason why attacking players , like Tal , loved to have isolated pawn.

                                               Game 2

It is more than obvious that the side that plays against the isolated pawn has to be more than careful to survive.

   Playing against the isolated pawn is not an easy thing and deep understanding of the aspects of the position is necessary.Even if you achieve a position like that in Diagram 3 , how will you progress?

    If we examine carefully Diagram 3 we will realise that white has achieved the ideal position against IP(isolated pawn).All his pieces are attacking the IP while black's pieces are tied down to it's defense.Still there is no obvious  way for white to make progress.Usually in these positions white can play e4 and d5 pawn is pinned, and because of that doomed, but in this position that is not an issue.Black can easily exchange pawns and rooks and draw.White seems to be in a dead end.

    In that case it is important to remember that often the weakness of the isolated pawn is not enough to give you the win.Once opponent's pieces are tied down to the defense of IP  you need to open a new front.The simultaneous attack on isolated pawn and on the new front will make opponet's defense almost impossible.Let's see how Botvinnik continued 

                                                 Game 3

In this amazing and very instructive game Black never lost the IP but he lost the game as he wasn't able to defend 2 fronts simultaneously.

Careful study of Game 3 is enough to convince us that , the fewer the pieces ,the more weak the IP is, but the common belief that the side with the IP is lost at any endgames is wrong.In fact , once the player with the IP realises that pieces are few and can't offer him any active play, he should strive for exchanges as it is his best chance to draw.Usually with no rooks in the game it is very difficult to create a pressure against the IP and launch a successful attack at a new front if needed. 

                                                Game 4

the more weak the IP is but the common belief that the side with the IP is lost at any endgames is wrong.In fact , once the player realises that pieces are few and can't offer him any active play he should strive for exchanges as it is his best chance to draw.Usually with no rooks in the game it is very difficult to create a pressure against the IP and launch a sucessful attack at a new front.