A single bad move can ruin the show

Chess Checks

One bad move in a game of chess can nullify all the previously played good moves. A certain victory could well end up in a draw or even a loss and hence there is no room for complacency at any given point in a chess game.

In the game which follows, white sacrifices an exchange and has no compensation for it. Just when victory is within striking distance, black blunders with a queen move and immediately ends on the losing side.

White: Ladislav Salai (2440) – Black: Dejan Mozetic (2470)
Bratislava, 1996
Sicilian Defence
1.e4 c5
The Sicilian Defence
2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 g6 5.Nc3 Bg7 6.Be3 Nf6 7.Bc4 d6 8.f3 Qb6
A sharp looking bur dangerous move! Black can keep it safe with 8. ..0-0 which is well studied
9.Nf5
Interesting! White can consider 9.Bb5
9...Qxb2 10.Nxg7+ Kf8 11.Nd5 Nxd5 12.Bxd5 Kxg7 13.0–0 Qc3 14.Re1 White can play 14.Qc1 h5 15.Rb1 Qa5 16.c4 e6 17.Bxc6 bxc6 18.c5 d5 19.Bd4+ f6 20.f4 Rf8 21.exd5 cxd5
14...f6
Better appears 14. ..Rd8 And if 14...Qa5  15.Qc1 h5 16.Qb2+ f6 17.Rad1 Qc7 18.f4 h4
15.Rb1 Qa5 16.f4 Qc7 17.Qd2
If 17.f5 Bd7 18.Rb3 Rac8 19.Qg4 b6 20.Rc3 Qd8 21.Ra3 Qc7 22.Bxc6 Bxc6 23.h4 Bd7 was also played previously
 17...h5 18.Rb3 Bd7 19.e5
White can think of 19.f5
19. ..dxe5 20.fxe5 fxe5 21.Rf1 Bf5
Black closes the file even as white tries to take control of this open file with his rook
22.Rxf5
White sacrifices his rook for the bishop to try and attack the vulnerable appearing Black King
22. ..gxf5 23.Bb6 Qd6
If 23...axb6 24.Rg3+ Kf8 25.Qh6+! Ke8 26.Be6! Rf8 27.Qxf8+ Kxf8 28.Rg8 checkmate
24.Rg3+ Kf8
If 24...Kh7 25.Qg5
25.Qg5 Ke8
If 25...Qxd5 26.Qg7+ Ke8 27.Qxh8+ Kd7 28.Qxa8 Qd1+ 29.Kf2 Qxc2+ 30.Kf3 Qd1+ 31.Kf2 Qd2+ 32.Kf1 Qc1+ 33.Kf2 Qb2+ 34.Ke1 Qxb6
26.Qg7
If 26.Bf7+ Kd7 (26...Kxf7 27.Qg7+ Ke6 28.Rg6+ Kd7 29.Rxd6+ Kxd6 30.Be3 Raf8 with a winning advantage for Black)

Diagram 1
26...Qh6
This move is a mistake and black loses all the advantage he held. He could have tried to force a win with 26...Qf6 27.Bf7+ Kd7 28.Rd3+ Kc8 29.Qxf6 exf6 30.Be6+ Kb8 31.Bc5 b6 32.Ba3 Rd8 33.Rxd8+ Nxd8 34.Bd5 Nb7 35.Be7 e4 36.Bxf6 a6 37.Be6 Ka7
27.Qf7+
Now white’s attack gets going
27...Kd7 28.Qxf5+ e6 29.Qf7+ Ne7 30.Bxe6+ Kc6
If 30. ..Qxe6  31.Rd3+ and black loses the Queen
31.Be3
White can wrap up quickly with 31.Rc3+ KxBb6  32.Qf2+ Ka6  33.Ra3+
31. ..Qf8
If 31...Qh7 32.Qf6
32.Bd5+ Kc7 33.Qe6 Nxd5 34.Qxd5 Rd8 35.Qxe5+ Kc8
If 35...Qd6 36.Bf4
36.Bd4
Once again white misses a quick win with 36.Bf4 Rd1+ 37.Kf2 Rd2+ 38.Ke1
36...Rh7. Black would have had some chances of saving half a point after 36...Rh6 Rh6 37.Rc3+ Rc6 38.Qe6+ Kc7 39.Be5+ Kb6 40.Qb3+ (40.Rb3+ Ka5 41.Bc7+ Rxc7 42.Qe1+ Ka4 43.Qe4+ Ka5 44.Qe1+) 40...Ka5
37.Rc3+  and black resigned for he cannot prevent checkmate after 37. .. Qc5 38.Rxc5+ Rc7 39.Qxc7
1–0

Diagram 2
White to play and checkmate
1.Qe6+ Rxe6.
If 1...Kh8 2.Qxe8 checkmate
2.Rf8 checkmate