comment: [%c_effect b3;square;b3;type;Mistake;persistent;true] A serious error, mortally weakening the queenside.
context: 1. e2e4  1... c7c5  2. g1f3  2... d7d6  3. d2d4  3... c5d4  4. f3d4  4... g8f6  5. b1c3  5... a7a6  6. c1e3 The English Attack is one of the most critical lines against the Sicilian Najdorf. The variations are extensively studied and tested both in grandmaster practice and in correspondence games, but new ideas can still be found, as we see in this game. 6... e7e5  7. d4b3  7... f8e7  8. h1g1 [%c_effect g1;square;g1;type;Interesting;persistent;true] An interesting and fresh move. Usually White prepares the advance of the g-pawn with f3 or even h3. 8... b7b5 This move has been played just once previously. 9. g2g4 A normal reply, but White has two interesting alternatives. 9... c8b7  10. d1d3 Not a very attractive square for the queen. 10... b5b4  11. c3d5  11... f6d5  12. e4d5  12... e8g8  13. g4g5  13... b8d7  14. e1c1  14... a6a5 The last moves from both sides are natural. The impression is that Black is a little ahead in the typical race that exists when the kings are on opposite sides. 15. b3d2  15... d8c7  16. c1b1  16... f8c8  17. d2e4  17... a5a4  18. f1h3  18... b7a6  19. d3d2  19... b4b3 Black's attack appears to arrive quickly, but the situation is not yet so desperate for White. 20. c2b3  20... a4b3 