Pawn island

A pawn island is a group of one or more same-colored pawns occupying adjacent files and separated from the other friendly pawns by at least one empty file. A file is a vertical line of the board. The pawns' horizontal positions do not affect the count; only their files matter.

A completely lone pawn counts as one island. Three pawns spread across neighboring files also count as one island even when they stand on different ranks. If an empty file follows and another friendly pawn appears farther away, a new island begins.

More islands usually mean more independent groups to defend. Pawns in one island cannot receive pawn support from another unless the structure first changes. As pieces are exchanged, a fragmented structure may therefore leave more targets. However, fewer islands do not guarantee an advantage: more active pieces, control of more squares, a pawn close to promotion, or king safety may matter more.

An island may contain connected pawns on consecutive files, a pawn chain staggered diagonally so that pawns protect one another, or doubled pawns, two friendly pawns on the same file. The term island describes separation between groups, not the internal quality of each group.