context: 1. d2d4  1... d7d5  2. g1f3  2... c7c5  3. c2c4  3... c5d4 An interesting position and not well-known at amateur level. It's not easy to demonstrate an advantage for White in this opening. 4. c4d5  4... g8f6  5. f3d4  5... f6d5  6. e2e4 