Chess basics have stressed that it is better to exchange pieces when a player has extra material in the form of pawns or pieces.
The simplification of the position then does not allow any the opponent any counter play. However, for the opponent it is important not to exchange pieces and complicate the position to try and gain counter play.
In the game which follows, White is clearly winning but fritters away the advantage by exchanging the queens which takes the fizz out of the game. From winning the game, White is compelled to seek draw by perpetual checks.
White: Raj Tischbierek (2490) – Black: Karen Movsziszian (2490)
Bad Woerishofen, 1997
Sicilian Defence
1.e4 c5 2.Nc3 d6 3.Nge2. This is not the usual continuation encountered in a Sicilian defence which is supposed to be a sharp defence.
3. ..Nf6 4.d4 cxd4 5.Nxd4 a6 6.Be3 e5 7.Nf3 Qc7 8.Be2 Be7 9.a4 0–0 10.0–0 b6 11.Qd3.
Even though it is not the usual Sicilian set-up, the variation has been played before
11. ..Bb7. If 11...Nbd7 12.Qc4
12.Qc4. An early invitation to swap queens.
If 12.Nh4 Rd8 (12...g6 13.Bh6 Rd8 14.Nf5 Bf8 (14...d5 15.Nxe7+ Qxe7 16.exd5 Nxd5 17.Nxd5 Bxd5 18.Qe3) 15.Bg5 Nbd7 16.Ne3) 13.Nf5 Bf8 14.Bg5 Nbd7 15.Ne3
12...Qd8. Black declines the invitation as it keeps the game on an even footing.
If 12...Qxc4 13.Bxc4 Nxe4 14.Nd5 Bd8 15.Bxb6 (15.Nxb6 Bxb6 16.Bxb6 Nd7) 15...Nd7 16.Bxd8 Rfxd8
13.Nd2 Nbd7 14.Rad1
If 14.Qb3
Rc8 15.Bc4 Nc5 16.Bxc5 Rxc5 17.Nd5 Nxd5 18.Bxd5 Bxd5 19.exd5 Qc7 20.c4
14...Rc8. Taking control of the open file
15.Qa2. This might look like a most unlikely square for the queen but it is the right move
15. .. Nc5. Better appears 15. ..Rxc3 16.bxc3 Nxe4 17.Nxe4
16.Bf3. White should have taken a look at 16.f3 Ne6 17.Nc4 Nd4
16. ..h6. If 16...Qc7 17.Bg5 Ne6 18.Bxf6 Bxf6 19.Bg4 Rfe8
17.Nc4 Qc7 18.Bxc5 Qxc5 19.Ne3 Qb4 20.Ncd5
White could have maintained equality with 20.Qb3
20...Nxd5 21.Rxd5
21...Bg5. If 21...Bxd5 22.Nxd5
22.c3 Bxd5 23.Nxd5 Qc5 24.g3 g6
Black could have seriously looked at 24. ..Ra8 25.Kg2 Qc6 . Black can also think about 24...Qc6
25.Bg4
White has lost a rook for the knight but now has enough compensation
25...Rb8 26.h4 Bd8 27.Bd7
A good move! This bishop is very active as he has infiltrated the enemy territory and is controlling a lot of space
27...a5 28.Rd1. Taking up positions!
28...b5 29.axb5 Qa7
Not exactly the right move. Black can try 28. ..Rxb5 29.Bxb5 Qxb5
30.Bc6 Kg7 31.b4 f5 32.exf5 Rxf5 33.bxa5 Bxa5
The correct move here is 33...Qxa5
34.Ne3 Rf7 35.Rxd6 Rbf8
The game has totally swung in White’s favour now. Black could have exchanged rooks with 35.Rd8
36.Qc2 Kh8 37.Qxg6 Rxf2 38.Qxh6+
If 38.Rd7 Rf1+ 39.Kh2 R8f2+ 40.Kh3
38...Qh7
Diagram 1
39.Qxh7+ . White should not have exchanged the queens but instead continued with the attack. The correct continuation is 39. Qg5 Bd8 40.Rxd8 Qg7
39. ..Kxh7 40.Be4+ Kh8 41.Rh6+ Kg8 42.Nd5 Re2 43.Bf5 e4 44.g4 e3 45.Rg6+ Kh8 46.Kf1 Rf2+ 47.Ke1 Rd8! 48.Rh6+ Kg8 49.Rg6+ Kh8 and draw by perpetual checks.
Diagram 2
White to play and win
1.Nd5 Rxd5. If 1...Ke8 2.Nxe7
2.Qh8 Checkmate.