1. e2e4  1... e7e5  2. g1f3  2... g8f6 The Petroff Defense continues to have an unshaken reputation as an indestructible defense, but the problem is that Carlsen is known for winning endgames in which he doesn't need an advantage. This explains his opening choice. 3. f3e5  3... d7d6  4. e5f3  4... f6e4  5. d1e2 When I was a kid this move, preparing the exchange of queens, had the reputation of being a ridiculous and blatant attempt to play for a draw, but post-Carlsen times have put an end to many preconceived ideas. 5... d8e7  6. d2d3  6... e4f6 