[%c_effect e4;square;e4;type;GreatFind;persistent;true] Suddenly, Black has a considerable advantage, as the pawn has ceased to be a weakness and has become a strength.
1. e2e4  1... d7d6  2. d2d4  2... f7f5 This is not a popular option, of course. Advancing the f-pawn is one of the worst things Black can do in a defense against the king's pawn opening. But, surprisingly, it's not as bad as it looks. Let's not forget this is a rapid game—some liberties are allowed. 3. e4f5  3... c8f5  4. f1d3  4... d8d7  5. g1f3  5... g8f6  6. d3f5  6... d7f5  7. e1g1  7... b8c6  8. c2c3 Too timid. 8... e7e5 A new move. 9. d4e5  9... d6e5 Black has a good position now. In exchange for an isolated pawn, he has good piece development. 10. f1e1  10... f8d6  11. h2h3 [%c_effect h3;square;h3;type;Mistake;persistent;true] This is too slow. White should control the e4-square as soon as possible. 11... e8c8  12. d1e2 