1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... g8f6 The Berlin Defense, widely considered Black's most reliable option against 1.e4, makes its first appearance in this duel. This is impressive, as a feature of world championship matches is that the openings are usually repeated. This is yet another feature that makes this match unique. 4. d2d3  4... f8c5  5. c2c3  5... e8g8  6. e1g1  6... d7d5  7. b1d2  7... d5e4  8. d3e4  8... a7a5 All of this is a critical variation of the Anti-Berlin and was played in an important game of the Candidates Tournament. The idea of this move is to gain space on the queenside and prevent b2-b4. 9. a2a4 A good option, fixing the pawn structure on the queenside. 9... d8e7 