1. e2e4  1... c7c5  2. g1f3  2... b8c6  3. f1b5  3... g8f6 Caruana used this move faithfully during the Candidates Tournament. 4. b5c6  4... d7c6  5. d2d3  5... d8c7  6. h2h3 A typical move, preventing …Bg4. It's not really necessary and it's probably not the most accurate, despite being the most played.