It's All About Squares

     We all know that the creation and exploitation of weak squares in the enemy position is an important element in modern strategy.  However, the weakness of a square is not an absolute factor.  Sometimes a weak square is of primary importance, other times its influence is negligible.  Everything depends on the character of the position, material, position of the pieces, etc. To recognize when a weak square is a real weakness and can be exploited calls for good strategic judgment because it's not a real weakness if it can't be exploited. For a good example of a strong N outpost see my discussion of the Smyslov vs. Rudakowski game here. 
     The following game is a good example of the importance of recognizing weak squares and how to use them and because learning by example is one of the best ways to learn anything, a close examination of the play of both players is sure to be helpful. In this game the battle is around Bisguier's attempt to advance his c-Pawn and Feuerstein's efforts at preventing it by controlling the c5 square. 
     First, a little background on the opening. At the Interzonal in Zagreb, 1955 Bisguier used his own variation against the advance ...e5 by black in the Sicilian against Gligoric, Udovcic and Barcza, all of whom met it with their own prepared lines, but without success. He was still using the variation successfully in 1957 when in the Manhattan Chess Club Championship Arthur Feuerstein put Bisguier's system to yet another test; he almost, but not quite, succeeded. Not long after this tournament Bobby Fischer invited Bisguier to play his system against against him in the US Open in Cleveland, Ohio.  Bisguier declined the invitation because he had an alternative prepared and managed to hold the draw. 
     Now for the game. Observe the struggle for control of c5.