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 