The h-pawn is defended so White can castle.
1. e2e4  1... c7c6  2. d2d4  2... d7d5  3. e4e5  3... c8f5  4. h2h4 This system is one of the most interesting ways of facing the Caro-Kann nowadays and is recommended for attacking players. 4... h7h5  5. g1f3  5... e7e6  6. f1d3  6... f5d3  7. d1d3  7... d8a5  8. b1d2  8... a5a6 A typical maneuver in this variation. 9. c2c4  9... g8h6  10. b2b3  10... h6f5  11. c1b2  11... f8e7 