1. g1f3  1... d7d5  2. g2g3  2... g7g6  3. f1g2  3... f8g7  4. d2d4  4... g8f6  5. e1g1  5... e8g8  6. c2c4  6... c7c6  7. b2b3 Carlsen used a version of this solid line to defeat Nepomniachtchi in their final test before their world championship match. 7... c8f5 The main line. 8. c1b2  8... b8d7  9. e2e3 This is the new trend, according to Megabase, that outshines the older 9.Nbd2. 9... f6e4 The most typical maneuver for the line. Black opens up his dark-squared bishop and prepares to swap a pair of light pieces.