Doubled pawns

In most cases, doubled pawns are considered a weakness due to their inability to defend each other.

This inability, in turn, makes it more difficult to achieve a breakthrough which could create a passed pawn (often a deciding factor in endgames).

Several chess strategies and openings are based on burdening the opponent with doubled pawns, a strategic weakness.

Also, if the opponent is unable to effectively attack the pawns, their inherent weakness may be of little or no consequence.

There are also a number of openings that accept doubled pawns in exchange for some prevailing advantage, such as the Two Knights Variation of Alekhine's Defence.