Isolani - Isolated Queen Pawn

Isolated Queen Pawn

An isolated queen pawn (IQP), called isolani is often a special case. An isolated queen pawn is one in the queen's file (d file). The weakness of such a pawn's isolation arises from two factors associated with the absence of both neighboring pawns:

1. Because the pawn is on one of the board's two central files (i.e., the d- or queen file), it blocks the opponent's control of that file and attacks or defends the other central file (i.e., the e- or king file). Given the strategic and (usually) tactical importance of control of the center, the pawn is important enough that the player must consistently defend it, but with no pawns available for its defense, the player must "tie down" a minor or major piece (in the opening, usually the king's knight or the queen) with that task.
2. Similarly, when the isolani is on the third or fourth rank, such that the square ahead of it is on the fourth or fifth rank (i.e., d4 or d5 respectively for White and the reverse for Black), the absence of adjoining pawns prevents the player from attacking or defending that square with pawns. Because each square is one of the board's four central and most important squares, the player will frequently be required to keep one or more pieces committed to the square's attack or defense.

However, the presence of open files in the important king and queen's-bishop (e and c) files as well as the outposts at e5 and c5 enable the player with the IQP very favourable attacking chances in the middlegame. Once the game reaches the endgame the isolated nature of the pawn becomes a greater weakness than these strengths. Therefore the player with the IQP must take advantage of the temporary strength before an endgame is reached. With four minor pieces each, an IQP is an advantage; with three minor pieces each, it is about even; and with two or fewer minor pieces each, it is a disadvantage (Gallagher 2002:140). Sacrifice of the pawn by White and blockade of the pawn by Black are common themes.