[%c_effect d5;square;d5;type;GreatFind;persistent;true] Now if Black captures with the pawn, White gets the b5-square. If she captures with the knight, then White gets the center.
1. g1f3  1... d7d5  2. g2g3  2... g7g6  3. f1g2  3... f8g7  4. d2d4  4... g8f6  5. c2c4  5... c7c6  6. e1g1  6... e8g8  7. a2a4 Only the eighth most popular move in this well-known position. 7... a7a5 A natural reaction, fixing the queenside. The b4-square is weakened, but White has an idea: