The computer Deep Fritz leads the world champion Vladimir Kramnik 2-1 after another slightly bemusing game played at the Art and Exhibition Hall of Germany in the Bonn Museum.

Kramnik was white and appeared to have the edge in his favourite Catalan Opening but the computer rather insouciantly gave up a pawn and emerged with a very active position. Kramnik was the one under pressure for the last few moves but sacrificed rook for bishop to set up a fortress position.

The champion had no explanation for his failure to notice a checkmate in one move in the previous game that ended with what is being dubbed ‘the blunder of the century’.

The third game followed the same opening as the first and Kramnik emerged ahead in development but in the middlegame the situation was reversed. Deep Fritz’s pressure, particularly against Kramnik’s queenside soon forced him to return the pawn. The computer’s queenside pawn majority was then a factor in all the possible endgames that could result and Kramnik had to defend carefully to draw.

As is so often the case the computer allowed him to give up material to set up a fortress as it has a materialistic tendency which regards such possibilities as favourable although a human can see the position will still be drawn 50 moves hence.

Annotated Game 3

Kramnik,V (2750) - DEEP FRITZ [E03]
The Duel Bonne GER (3), 29.11.2006

1.d4 Nf6 2.c4 e6 3.g3 d5 4.Bg2 dxc4 5.Qa4+ Again a Catalan and again Kramnik is wary of any lines which gambit the c4 pawn and opts to regain it immediately. 5...Nbd7 6.Qxc4 a6 7.Qc2 In game 1 Kramnik played 7.Qd3 and secured a slight edge but the Fritz programmers are allowed to made small modifications to the computer's opening book mid-match. 7...c5 8.Nf3 b6 9.Ne5 Nd5 10.Nc3 Bb7 11.Nxd5 Bxd5 12.Bxd5 exd5 13.0-0 Nxe5 14.dxe5 Qc8 Otherwise Rd1 would be awkward along the d file. 15.Rd1 Qe6 Remarkable play by the computer which has calculated a deep variation. Although Deep Fritz is disobeying the general principles of development it/^s position is absolutely fine. 16.Qd3 Be7! 17.Qxd5 Rd8 18.Qb3 Rxd1+ [18...Qxb3 19.Rxd8+ Kxd8 20.axb3 a5 21.Bd2] 19.Qxd1 0-0

[19...Qxe5? 20.Qa4+ b5 21.Qxa6] 20.Qb3 [20.Bf4!? f6 (20...g5 21.Bd2 Rd8 22.Qc2 Qxe5 23.Bc3 Qe6 24.b3 and my version of Fritz tends to prefer Black although I cannot accept that. However Black is not worse.) 21.exf6 Bxf6 22.Qb3 Re8 23.Qxe6+ (23.Be3 Qxb3 24.axb3 a5 25.Rb1 Re4 going to b4 is good for Black.) 23...Rxe6 wins back a pawn on b2 or e2 with advantage or in this line] 20...c4 21.Qc3 f6! Now Fritz wants to make the sacrifice of a pawn permanent because it will have pressure on a2, b2 and e2 as well as mobile queenside pawns. 22.b3 [22.exf6 Qxe2 23.fxe7 Qxf2+ 24.Kh1 Qf1#] 22...Rc8 23.Bb2 b5 Kramnik must prevent b5-b4 and c4-c3. 24.Qe3 fxe5! A very far sighted pawn sacrifice but we should not be surprised. Deep Fritz is looking at least nine moves ahead for both sides. 25.bxc4 Rxc4 26.Bxe5 [26.Qxe5 Qxe5 27.Bxe5 Re4 28.Bf4 Rxe2 29.Kf1 Rc2 30.Re1 Kf7 31.Re2 and the queenside pawns give Black the edge.] 26...h6! Fritz declares that Kramnik cannot improve his position as moving the rook weakens the a2 pawn. 27.Rd1 [27.Bd4 Qxe3 28.Bxe3 (28.fxe3 the position is about equal.) 28...Ra4 followed by Bf6 gives Black a big advantage.] 27...Rc2 28.Qb3 Qxb3 29.axb3 Rxe2 30.Bd6 Bf6 31.Bc5 a5 Fritz's pawn majority gives it slight winning chances and Kramnik has to tread a little carefully. 32.Bd4 Be7 [32...Bxd4 33.Rxd4 Rb2 34.Rd8+ Kf7 35.Ra8=] 33.Bc3 a4 34.bxa4 bxa4 35.Rd7 Bf8 36.Rd8 Kf7 37.Ra8 a3

38.Rxf8+! A strong human player can see this is a draw, to a computer it looks like material loss. 38...Kxf8 39.Bb4+ Kf7 40.Bxa3 Ra2 41.Bc5 g6 42.h4 Kf6 43.Be3 h5 44.Kg2 Kramnik has an unbreachable fortress. 1/2-1/2