comment: 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.
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.