Weakness
In the endgame, isolated pawns are a weakness in pawn structure because they cannot be defended by other pawns as with connected pawns. In this diagram, the white pawn on the e4 square and the black pawn on a7 are isolated.
Isolated pawns are weak for two reasons. First, the pieces attacking them usually have more flexibility than those defending them. In other words, the attacking pieces enjoy greater freedom to make other threats (win pieces, checkmate, etc.), while the defending pieces are restricted to the defense of the pawn. This is because a piece that is attacking a pawn can give up the attack to do something else, whereas the defending piece must stay rooted to the spot until the attacking piece has moved. The defending piece is thus said to be "tied down" to the pawn.
The second reason is that the square immediately in front of the isolated pawn is weak, since it is immune to attack by a pawn (often providing an excellent outpost for a knight). Thus an isolated pawn provides a typical example of what Wilhelm Steinitz called weak squares.
Read more about this topic: Isolated Pawn
Famous quotes containing the word weakness:
“I think that we may safely trust a good deal more than we do. We may waive just so much care of ourselves as we honestly bestow elsewhere. Nature is as well adapted to our weakness as to our strength.”
—Henry David Thoreau (1817–1862)
“A little cooling down of animal excitability and instinct, a little loss of animal toughness, a little irritable weakness and descent of the pain-threshold, will bring the worm at the core of all our usual springs of delight into full view, and turn us into melancholy metaphysicians.”
—William James (1842–1910)
“If weakness may excuse,
What murtherer, what traitor, parricide,
Incestuous, sacrilegious, but may plead it?
All wickedness is weakness: that plea therefore
With God or man will gain thee no remission.”
—John Milton (1608–1674)