Pawn island
A pawn island is a cluster of one side's pawns on neighboring files, separated from that side's other pawns by a file without any of its pawns, and fewer islands usually signal a healthier structure.
To count islands, look at one side's pawns file by file and start a new group wherever a file holds none of them. With pawns on the a, b, d, g and h files you have three islands: a and b, d alone, and g and h. Doubled pawns do not add islands, since two pawns on the same file still sit in one group.
Why does the count matter? Inside a group, pawns can guard one another, but the pawn at the back of each group has nobody behind it, so pieces have to look after it. Every extra island therefore creates another pawn that needs piece protection, and a group of one is an isolated pawn. In the endgame, when few pieces are left to do that job, the side with more islands is the one under strain.
The count is a guide, not a verdict. Active pieces, a safe king or a lead in development can outweigh a worse structure in the middlegame.
To improve your own count, trade off a lone pawn or link two groups by advancing a pawn between them. Against the opponent's islands, look for the separated groups and aim at the pawn that has the fewest defenders.
Where "Pawn island" fits your own play is easier to judge with a coach reading your games; the first lesson is a paid one-on-one review that ends in a written plan.
Related terms
An isolated pawn is a pawn with no friendly pawn on either neighboring file, so no other pawn can ever defend it and the square in front of it is a lasting weakness.
Doubled pawns are two of one side's pawns stacked on the same file, usually after a capture, and they tend to be a structural weakness because neither can guard the other.
A weak pawn is a pawn that is hard to defend with other pawns and so must be protected by pieces, making it a long-term target for the opponent.
A pawn majority is a larger number of pawns on one wing or in one area of the board than the opponent has there, giving the chance to create a passed pawn.
Connected pawns are two or more friendly pawns standing on adjacent files, side by side or on neighboring ranks, so that they can support each other as they advance.
A half-open file is a file on which one side has no pawn while the opponent still does, giving the side without a pawn a line along which to attack the enemy pawn.
Guides that go further
What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.
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