1. Nf3

One of a family of openings that can easily transpose into each other - 1. c4 English, 1. g3, 1.b3 or Nf3 + b3 Nimzowitsch-Larsen attack, 1. e3 Van't Kruijs opening, Catalan opening, King's Indian Attack. The game can also transpose into the Sicilian Closed variation.    Its main drawback is that White is committed to the   Knight on f3 and therefore lacks option of f3 as in King’s Indian Saemisch variation, if Black plays King’s Indian defence.

1... c5

I believe that this is the best reply. Against 1....d5 Reti, KIA, Nimzo-Larsen and Catalan are effective for White.  2. g3  {2. e4 will be a Sicilian 2. c4 see 5. c4 below} g6  This is an excellent development, but Black should not be in a rush to play Nc6 as White can often play c3 or e3 and d4. This will produce a threat of d5 against the Knight on c6. Also Black should not play an early Nf6 as the Knight is nearly always much better on e7 in this line. 3. Bg2  This position, of course, will often arrive from 1. g3. I do not believe that it is very effective for White here as the Knight is often better on e2.

 

3... Bg7 4. O-O

[4. d4 If White wants to play d4 he had better play it now as Black will soon get a clamp on the d4 square. cxd4 5. Nxd4 Nc6 There is no pressure on the Black position, Black has good play. 53% Black 282 games

 (5... d5 6. O-O e5 7. Nb5 a6 8. N5c3 d4 is an alternative, but Black may be overstretched);

4. c4 Nc6 5. e3 e5 6. Nc3 Nge7  81% in 8 !]

4... Nc6 Now White has to make his mind up. If he continues c4 the game will take on an English character. If he plays e4 the game will be akin to a Closed Sicilian, d3 is mainline KIA. 5. c4 This can arise from the Symmetrical English opening, where White has neglected to take action in the centre with d4.

[5. d3 King's Indian Attack d6 (5... d5 Black can also take the centre if he wishes. 6. Nbd2 (6. e4 Nf6!) 6... e6 7. e4 Nge7 8. Re1 b6 is an excellent alternative -  >54% in 546 games

) 6. e4 e5 Black is solid  58% in 623 games. As can be seen the difference is that the Black Knight going to e7 gives better possibilities than the White Knight slightly misplaced on f3.

;

5. e4 e5 6. c3 White dreams of playing d4. Nge7 7. d3 O-O 8. a4 h6 9. Na3 d5 But Black makes the break. 10. exd5 Nxd5 11. Re1 Re8 12. Nd2 Be6 13. Ndc4 Qd7 14. a5 Rad8 15. Qa4 a6 16. Be3 Bf8 17. Rad1 f5 18. Bc1 Bf7 19. Nb6 Nxb6 20. axb6 Bd5 21. Bxd5 Qxd5 22. Qc4 Na5 23. Qa4 Nc6 24. Qc4 Kg7 25. Qh4 Kh7 26. Nc4 Bg7 27. g4 f4 28. Qh3 e4 29. Bxf4 exd3 30. Ne3 Qf7 31. Bc7 Rd7 32. Rf1 c4 33. Qg3 Bf8 34. Qf4 Qxf4 35. Bxf4 Bc5 36. Rfe1 Re4 37. Bc7 Rde7 38. b3 Bxe3 39. Rxe3 Rxg4 40. Bg3 Rxe3 41. fxe3 cxb3 42. Rb1 Ra4 43. Kf2 Na5 44. e4 Rxe4 45. Kf3 Re6 0-1, Maherramzade Javad - Kotsur Pavel 2581 , Abudhabi 2003 It (open) ;

5. c3 e5 6. d3 Nge7 54% in 88 games.]

5... e5  ! This is called the Botvinnik Blockade System.   Black gets a hold on d4, and can attack on either wing {or even in the centre with d5 occasionally ! 55% in 364 games ! 6. Nc3 Nge7 All Black's pieces are harmoniously developed.  7. a3 O-O 8. d3 d6 9. Rb1 a5  Black will play moves like h6, Be6 f5 ! with excellent prospects  - 57% in 378 games.