1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... d7d5  4. c4d5  4... e6d5  5. c1g5 World championship matches give a popularity boost to the lines that were explored there. 5... c7c6  6. e2e3  6... h7h6  7. g5h4  7... f8e7  8. f1d3  8... e8g8  9. d1c2  9... f8e8 The Carlsbad pawn structure has been reached, one of the most solid setups. 10. g1e2  10... a7a5 A useful, and flexible move. 11. h2h3  11... b8a6 [%c_effect a6;square;a6;type;Interesting;persistent;true] Another flexible developing move. The knight is ready to proceed to the e6-square, whenever needed.