Strong square

A strong square is a favorable location for one of your pieces. From it, a piece may control routes, attack targets, support teammates, or enter enemy territory while the opponent has few effective ways to dislodge it. Strength comes from the relationship between the square and the position, not from the square alone.

Many strong squares appear after an enemy pawn advances or is exchanged and can no longer control them. The same location may therefore be a weak square for one side and a strong square for the other. Yet the absence of pawn control is not enough: the square must be reachable and give the occupying piece useful work.

Potential strength and actual strength

An empty square is only a possibility. It becomes a real advantage when the right piece can occupy it, remain there, and create threats or restraint. A secure central knight is the clearest example, but a rook on a key file, meaning a vertical board line, or a bishop using an important diagonal can also benefit from a strong location.

An outpost is a narrower case. It is usually an advanced square that an enemy pawn cannot attack and where a piece can settle securely. A strong square may be farther back, serve a defensive purpose, or matter only as a staging point in a maneuver.