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:
“The whole fauna of human fantasies, their marine vegetation, drifts and luxuriates in the dimly lit zones of human activity, as though plaiting thick tresses of darkness. Here, too, appear the lighthouses of the mind, with their outward resemblance to less pure symbols. The gateway to mystery swings open at the touch of human weakness and we have entered the realms of darkness. One false step, one slurred syllable together reveal a man’s thoughts.”
—Louis Aragon (1897–1982)
“What knows,—the something over Setebos
That made Him, or He, may be, found and fought,
Worsted, drove off and did to nothing, perchance.
There may be something quiet o’er His head,
Out of His reach, that feels nor joy nor grief,
Since both derive from weakness in some way.”
—Robert Browning (1812–1889)
“It is from a weakness and smallness of mind that men are opinionated; and we are very loath to believe what we are not able to comprehend.”
—François, Duc De La Rochefoucauld (1613–1680)