The Illusory Pawn Sacrifice

The illusory pawn sacrifice looks like a concession but is, in fact, a sound investment: the pawn is regained with interest, or the material given up buys lasting positional gains. Recognising such 'sacrifices' saves the defender from taking the bait. Each example explains why the pawn was never really lost.

White's plan is obvious: b2-b4-b5. But the b4 square is under Black's control. Possible is 1.a3 and then b2-b4-b5. But evidently the move 1.a3 will turn out to be an extra move in the further play. Much stronger looks 1.Rb1 and then b2-b4-b5. But it is quite possible that 1.Rb1 will also prove superfluous, since in the future the maneuver a2-a4-a5-a6 may be needed, and for that the rook must be on a1. So both moves, 1.a3 and 1.Rb1, threaten a loss of time, of which White do not have much anyway - Black are ready for the f7-f5 counterattack. Therefore, taking into account the undefended b7 pawn and the guarantee of a return, White played.