This is the idea behind ​​White's play. The knight finds a good square on b5.
1. e2e4  1... e7e5  2. f1c4  2... g8f6  3. d2d3  3... c7c6  4. g1f3  4... d7d5  5. c4b3  5... a7a5  6. a2a4  6... f8b4  7. c2c3  7... b4d6  8. e4d5  8... c6d5  9. c1g5  9... c8e6 