It's always a difficult decision for White in the Ruy Lopez, whether to play d5 or to take the e5-pawn.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... a7a6  4. b5a4  4... g8f6  5. e1g1  5... f8e7  6. f1e1  6... b7b5  7. a4b3  7... d7d6  8. c2c3  8... e8g8  9. h2h3  9... c6b8 The good old Breyer Variation of the Ruy Lopez remains popular to this day. At one point it was one of Magnus Carlsen's favorite defenses. 10. d2d4  10... b8d7  11. b1d2  11... c8b7  12. b3c2  12... f8e8  13. d2f1  13... e7f8  14. f1g3  14... a6a5 A very rare plan. The overwhelming majority of games continue with 14...g6. Black advances the pawn to a4, gaining some space and preventing White from playing the typical a2-a4. 15. c1d2  15... a5a4  16. c2d3  16... c7c6  17. d1c2  17... d8b6  18. d2e3  18... b6a5  19. e3d2  19... a5b6  20. a1d1 This natural move is a novelty, but now Black is able to solve the opening problems. 20... c6c5 [%c_effect c5;square;c5;type;GreatFind;persistent;true]