Here's a nice White-to-play-and-win position from the Masters section of the Hampstead Chess Festival.

Jacob Aagard, who went on to win the tournament, was White, playing against Miroslav Houska. He has sacrificed the exchange and needs a way to get his e-pawn out of the path of the bishop on d4 when Black will be mated. If you haven't spotted the answer, just head for move 34 in the score of the game opposite.

The game is a good example of the change that has come over an important line in the Sicilian Defence in recent years. At the start of the 1990s, an early g4 for White was generally thought faulty unless played in conjunction with Q-side castling. In the system with Be2 and 0-0, it was viewed with great suspicion. It gave White a temporary initiative but was thought in the long run to weaken White's own king more than was acceptable.

A string of games such as this one, however, have shown how powerful White's attack can become.

White: Jacob Aagard

Black: Miroslav Houska

1 e4 c5 19 e5 d5

2 Nf3 e6 20 Qf4 Qe8

3 d4 cxd4 21 Na4 Bd7

4 Nxd4 Nf6 22 Nb6 Rd8

5 Nc3 d6 23 Bd4 Bb5

6 Be2 a6 24 Rf2 Kg7

7 0-0 Be7 25 a4 Bc6

8 f4 0-0 26 c3 Kg8

9 Be3 Qc7 27 h4 Kg7

10 g4 Nc6 28 Qf3 Kg8

11 g5 Nxd4 29 Qh3 Bd7

12 Qxd4 Nd7 30 Nxd7 Qxd7

13 f5 Re8 31 Rxf8+ Kxf8

14 fxe6 fxe6 32 Bxe6 Qe8

15 Bh5 Rf8 33 Qf3+ Kg7

16 Rxf8+ Nxf8 34 Qf6+ Bxf6

17 Rf1 g6 35 exf6+ Kf8

18 Bg4 Qc6 36 Bc5+ resigns