A logical  novelty. In the arising Carlsbad pawn structure, White is getting ready to attack on the kingside. For starters, he waits for his opponent to castle. 
1. d2d4  1... g8f6  2. g1f3  2... d7d5  3. c1f4  3... c7c5  4. e2e3  4... d8b6  5. b1c3  5... c8d7  6. a1b1  6... e7e6  7. f1e2  7... b8c6  8. e1g1  8... c5d4  9. e3d4  9... a8c8  10. a2a3  10... f8e7 