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 