context: 1. e2e4  1... c7c6  2. d2d4  2... d7d5  3. e4e5  3... c8f5  4. h2h4 This is one of the most interesting and popular options in the Advance Variation of the Caro-Kann. Black really needs to know what to do here. 4... h7h5 This is considered the best move by theory, stopping the dangerous advance of the kingside pawns. 5. f1d3 White reverts to a simpler strategy, exchanging bishops and trying to demonstrate that the inclusion of h4-h5 helps his position, since Black's king remains in danger with such a pawn formation. 5... f5d3  6. d1d3  6... d8a5 This check looks like a beginner's move, but it has the strategic idea of putting the queen on a6. White, naturally, doesn't want to exchange queens. 7. b1d2  7... e7e6  8. g1f3  8... a5a6  9. c2c4 This is why White placed the knight on d2. 9... g8h6  10. e1g1  10... h6f5  11. b2b3  11... b8d7  12. a2a4 After this move White has a comfortable advantage, so Black's previous play needs to be improved. The problem here is the space advantage, the lack of counterplay, and the king being in danger because the white knight has an inviting square on g5. White's last move aims to exchange the bishop with Ba3, since after all the white bishop is limited by the pawn chain. 12... f8b4  13. c1a3 