4.f3

W wants to etablish a strong center with e4, and keeps the two bishops advantage
B does react energetically by c5/d5

TIP : with f3, bear in mind Qh4+

• 4... d5
  • 4... O-O 5. e4 d5 6.e5 Nfd7 7. cxd5 exd5 8. f4
  • 4... c5 5. d5 exd5
    • 5... b5?! 6. e4 bxc4 7. Bxc4 Nxd5 8. Bxd5 (8. exd5 ? Qh4+ 9. g3 Bxc3+ 10. bxc3 Qxc4 11. dxe6 fxe6) 8... exd5 9. Qxd5 Nc6)
    • 5... Bxc3+? (W doesn't play a3, this donates a free tempo ) 6. bxc3 O-O 7. e4 !
  • 6. cxd5 d6 7. e4 O-O 8. Nge2 Nh5 ?! {B frees the queen to h4+ and prepares f7-f5}
• 5. a3 Bxc3+ 6. bxc3
  • 6...c6 7. Qc2 O-O (7... dxc4 8. e4 !) 8. cxd5 (8. e4? dxe4 9. fxe4 e5 !) 8... cxd5
  • 6...c5 see E25
• 5. a3 Be7+ 6. e4
  • 6...dxe4 7. fxe4 e5! 8. d5 Ng4 9. Nf3 Bc5
  
  
  
  10. b4 Bf2+ 11. Ke2 c5 12. Nb5 a6 13. Qa4 axb5 14. Qxa8 Na6 15. cxb5 Nc7 16. Qa5
  
  
  • 6... O-O 7. e5 Nfd7 8.cxd5 Nb6 9.Bd3 N
    • Timofeev Artyom - Iordachescu Viorel Moscow Open 2008
      • Echecs X
      • Moscow open 2008
  • 6... c5