If the <BD>pawn</BD> at <BD>f6</BD> is immediately moved to <BD>f5</BD> then <BD>black</BD> can win the game. <BD>Timing</BD>  is crucial because the opponent might otherwise advance towards e5 in an attempt to separate the opponent's pawn from the rest of its pieces.

Try it:     <BD>f6 - f5</BD>;
            <BD>f5 - e5</BD>;
            <BD>e5 - a3</BD>....