4.a3 Bxc3 5.Bxc3 g6 6.Bb4 Ne4 7.Qf4 Nfg3! 8.Qe5 Qd7 9.Rxc8 Rxc8 10.Bxe4 Nxe4 11.Rf1 Qe6! 12.Qxe6 fxe6
White methodically improves his position, waiting with Nf3-e5 until the f4-pawn is safe, and a pin with Bh5 no longer exists.
With the centre dominated by his strong knight, White launches a kingside attack.
Heading for f8-g6-h4 with kingside pressure. Besides, on g6 the knight will be useful in eyeing the f4-pawn.
Leaving the king under a cloud. Preferable was 6.Qxf6 Rxf6 7.Nd1 heading for e3.