A typical maneuver in the Italian.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1c4  3... f8c5  4. e1g1  4... g8f6  5. d2d3  5... d7d6  6. c2c3  6... a7a5  7. f1e1  7... c5a7  8. c4b3  8... h7h6  9. b1d2  9... e8g8  10. h2h3  10... c8e6 Antipov has some experience in this position. 11. b3a4 The a4-square is a natural one for the bishop when Black has played the pawn to a5 and not a6, since now b7-b5 is not available.