Gaining some space on the kingside, before Black achieves the same thing by 1...h5.

White is also better after 3...h6 4.Bxd6 Kxd6 5.Nf4! , preparing g4-g5.

This leads to a bad structure. 6...Bf5 should have been played.

White wins a pawn with a huge advantage.

Gaining space and chasing away the active black knight.

Preparing a4-a5.

Stepping up the pressure.

Thanks to the weak pawns on a6 and c7 White is clearly better.

Preparing a pawn storm on the queenside with b2-b4 and a2-a4. 1.a3?! is less precise, since after1...f6 2.b4 Nf7 White will have to spend one more tempo protecting the b-pawn before he can push a3-a4.