A weak square — often called a hole — is a square that you can never again defend with a pawn, which makes it a permanent parking spot for an enemy piece. Once your pawns have moved past it or disappeared, that square is weak for good; pawns only move forward, so there’s no taking it back.
Weak squares are usually born from pawn moves. Every time a pawn advances, it stops guarding the squares it used to cover — push a pawn and you may leave a hole behind it. The most dangerous holes are in your own half of the board, on squares an enemy knight can reach and settle on. A single well-placed hole can haunt you for the entire game, because the piece that lands on it simply can’t be chased off.
Why it matters
Spotting weak squares — both yours to fix and the enemy’s to exploit — is a core positional skill. Ask before every pawn push: what square am I giving up forever? On offense, hunt for the enemy’s holes and steer a knight toward them. Weak squares often cluster by color (a “weak color complex”), especially after the bishop that covered them gets traded off — which is why a bad bishop and weak squares of that color so often go together.
Related terms
A weak square that you actually occupy with a piece becomes an outpost — the two concepts are inseparable. Holes commonly appear in front of a backward pawn or beside a locked pawn chain, and the d5 hole is a defining feature of the Sicilian Najdorf. More terms in the chess glossary.
Mini-FAQ
What’s the difference between a weak square and an outpost? A weak square is the hole itself; an outpost is that hole once you’ve planted a piece on it. Same square, active vs. potential.
Are all holes serious? No — a hole far from the action or one the enemy can’t reach may never matter. The dangerous ones are central squares a knight can occupy.
Written and fact-checked by the Chess Lab Academy Editorial Team (AI-assisted, human-edited) · Position legality verified with python-chess; definition checked against Wikipedia and standard chess literature · Last verified 2026-07-13 · How we verify content.