1. e2e4  1... e7e5  2. g1f3  2... g8f6 Here we have the good old Petroff again. Is this defense taking the Berlin's place as Black's bulletproof option against 1. e4 $2 3. d2d4  3... f6e4  4. d4e5  4... d7d5  5. b1d2  5... e4d2  6. c1d2  6... f8e7  7. f1d3  7... c7c5  8. c2c3  8... c8g4  9. h2h3  9... g4h5  10. d3f5 Muzychuk had put her bishop on f5 also in the first game and now tries it six moves earlier. It's a new and interesting idea. In combination with g2-g4, the bishop on f5 creates discomfort for Black. I remember analyzing a similar idea in the Open Ruy Lopez. 10... b8c6  11. g2g4  11... h5g6  12. d1e2 This is the idea. White plans to castle queenside and then play h4-h5. Black needs to be fast. 12... d8b6 Too slow. 13. e1c1  13... g6f5 A sad necessity. 14. g4f5  14... e8c8  15. h1g1  15... h8e8 A move that looks interesting, sacrificing a pawn, but White gets the advantage. I must remember that this was a rapid game, so this move was a good practical chance. 16. g1g7  16... e7f6  17. g7f7  17... f6e5  18. e2f1 The machine indicates a greedy continuation that gives White a winning advantage. 18... b6a5  19. c1b1  19... a5a4  20. d2g5 This move allows Black an incredible resource, as the c3-pawn is now susceptible to a sacrifice from the black bishop. 20... d8d6 Missing the chance, but to be honest the idea is nearly impossible to find. 21. f7h7  21... e5c3 This time Koneru seizes the opportunity. 22. b2b3  22... a4a5  23. g5f4  23... c6b4  24. a2a4  24... d6c6 This move loses. 25. f1b5 A surprising and spectacular move. 25... a5b5  26. a4b5  26... e8e2 The last chance. 27. f4d2  27... c3d2  28. b5c6  28... d2c3  29. c6b7  29... c8b8  30. d1g1 This move allows perpetual check. 30... e2b2 