Two weaknesses — what it means in chess
The principle that converting often needs a second target alongside the first.
The principle that converting often needs a second target alongside the first.
The principle of two weaknesses is the master's method for winning won positions: one weakness can usually be defended, so create a second one, far away, and stretch the defense between them until it tears. The defender's pieces can hold a single target from good squares indefinitely — but two targets on opposite wings force them to commute, and every commute arrives one tempo late somewhere.
The method explains the strange patience of strong players in better positions. The extra pawn is not pushed; the weak square is not cashed; instead, play opens on the other wing, probing until something else becomes fixed and attackable. Then the position plays itself: attack the first weakness, and when the defense gathers, switch. The technique is the practical engine behind space advantages — the side with more room switches wings faster — and its endgame form runs on zugzwang, where the stretched defender must eventually let go of something because passing is not among the rules.
If a single principle separates positional mastery from positional competence, it is this one: the first weakness wins the evaluation, and the second one wins the game. It is the last word in a plan well made — and a fitting last entry for this glossary's strategy shelf.
The Endgame Society glossary defines more than 240 chess terms — rules, notation, tactics, strategy, pawn structures, endgames, and openings — in language a beginner can act on rather than dictionary shorthand.