Weak Squares & Outposts

A WEAK SQUARE (a 'hole') is a square no enemy pawn can ever attack again — the neighboring pawns have advanced past it or left the board. Pawns can't move backward, so the hole is PERMANENT.

An OUTPOST is a hole you occupy — ideally with a knight, protected by your own pawn. A knight on a central outpost is often worth more than a rook: it attacks everything and nothing can ever chase it away.