An outpost is a square on the fourth, fifth, sixth, or seventh which is protected by a pawn and which cannot be attacked by an opponent's pawn. Such a square is a

hole A hole is an opening in or through a particular medium, usually a solid Body (physics), body. Holes occur through natural and artificial processes, and may be useful for various purposes, or may represent a problem needing to be addressed in m ...

for the opponent . In the figure to the right, c4 is an outpost, occupied by White's knight. It cannot be attacked by Black's pawns – there is no pawn on the d- and Black's pawn on the b-file is too far advanced. Outposts are a favourable position from which one can launch an attack, particularly using a

knight A knight is a person granted an honorary title of a knighthood by a head of state (including the pope) or representative for service to the monarch, the church, or the country, especially in a military capacity. The concept of a knighthood ...

. An outpost is even more effective where it is difficult to trade off with an equal valued piece, e.g., if the opponent only has a bishop of the opposite color to the outpost square's color. Knights are most efficient when they are close to the enemy's stronghold. This is because of their short reach, something not true of

bishops A bishop is an ordained member of the clergy who is entrusted with a position of Episcopal polity, authority and oversight in a religious institution. In Christianity, bishops are normally responsible for the governance and administration of di ...

, rooks and

queens Queens is the largest by area of the Boroughs of New York City, five boroughs of New York City, coextensive with Queens County, in the U.S. state of New York (state), New York. Located near the western end of Long Island, it is bordered by the ...

. They are also more effective in the centre of the board than on the edges. Therefore, the ideal to be aimed at is an outpost in one of the central (c-, d-, e- or f-) files in an advanced position (e.g. the sixth rank) with a knight. Knowledge of outposts and their effectiveness is crucial in exploiting situations involving an isolated queen's pawn. On the other hand, Nimzowitsch argued when the outpost is in one of the flank (a-, b-, g- and h-) files the ideal piece to make use of the outpost is a rook. This is because the rook can put pressure on all the squares along the rank.

References

Bibliography * * {{chess Chess terminology Chess strategy