Accurate defence from Kramnik secured him a draw in the fourth game of his match against the computer Deep Fritz. Overall Kramnik has not looked inferior to the machine and had he not made that horrific blunder in the third game he would be looking to the last two games with confidence but now he trails 1.5-2.5 with two to play. Playing Black Kramnik was soon in some difficulties as the computer reached an open position in which its massive calculating power is difficult to counter but Kramnik held on with some far sighted defensive manoeuvres.

The contest is being sponsored by the German energy company RAG and staged at the Art and Exhibition Hall of the Bonn Museum. Kramnik will double his start money of $500,000 if he wins the last two games.

Annotated Game 4

DEEP FRITZ - Kramnik,V (2750) [C43]
The Duel Bonne GER (4), 01.12.2006
Notes IM Malcolm Pein

1.e4 e5 2.Nf3 Nf6 The Petroff Defence which is the most solid choice. The pawn structure is often symmetrical. 3.d4 Nxe4 4.Bd3 d5 5.Nxe5 Nd7 6.Nxd7 Bxd7 7.0-0 Bd6 8.Qh5 Qf6 This pawn sacrifice is known. [8...Nf6 9.Re1+ Be6 (9...Kf8 10.Qe2 c6 11.Nd2 Qc7 12.Nf3 Bg4 13.Qe3 Bxf3 14.Qxf3 Bxh2+ 15.Kf1 Bd6 16.Bg5 Qd8 17.Qh3 Be7 18.Re3 Ng8 19.Rxe7 Nxe7 20.Re1 f6 21.Bd2 a5 22.Qe6 Ng8 1/2-1/2 Sutovsky,E (2607)-Eljanov,P (2651)/Montreal CAN 2006/The Week in Chess 615) 10.Rxe6+ Kf8 11.Rxf6 gxf6 12.Nc3 c6 13.Bh6+ Ke8 14.Bf5 Qc7 15.Bg7 Rg8 16.Re1+ Kd8 17.Bxf6+ 1-0 Jacob,R (2015)-Jonas,T/Sao Paulo BRA 2006/The Week in Chess 624] 9.Nc3 [9.Be3 g6 10.Qxd5 Bc6 11.Bb5 Bxb5 12.Qxb5+ c6 13.Qd3 Ng5 14.f4 Ne6 15.Nc3 Qe7 16.Ne4 f5 17.Nxd6+ Qxd6 18.Qb3 0-0-0 19.Rad1 Qd5 20.c4 Qe4 21.d5 Nc7 22.dxc6 Qxc6 23.Bxa7 Rxd1 24.Rxd1 Re8 25.Be3 Re4 26.Qd3 Ne6 27.b3 Qc7 28.g3 h5 29.Kf2 h4 30.Qd6 hxg3+ 31.hxg3 Qh7 32.Rg1 Qh2+ 33.Rg2 Qh1 34.Qd2 Kc7 35.c5 Kc8 36.Qc1 Qxc1 37.Bxc1 Nxc5 38.Bd2 Kd7 39.Kf1 Kc6 40.Re2 Kd5 41.Bc3 Nd3 42.Bd2 Nc5 43.Rxe4 Nxe4 44.Be1 Kd4 45.Ke2 Nc3+ 46.Bxc3+ Kxc3 47.Ke3 b6 48.Ke2 Kc2 49.Ke3 Kc3 50.Ke2 1/2-1/2 Majzlan,I (2190)-Rohacek,M/Bratislava 1997; 9.Qxd5 Bc6 Black gets a kingside attack.] 9...Qxd4 [9...Nxc3 10.bxc3 h6 11.Re1+ Be6 12.Qxd5 0-0-0 13.Qa5 Bd5 14.c4 Bc6 15.Be3 Kb8 16.Rab1 Bf4 17.d5 Bxe3 18.Rxe3 Bd7 19.Be4 Bc8 20.c5 Rhe8 21.Rf3 Qd4 22.Ra3 a6 23.Ra4 Qf6 24.d6 cxd6 25.Bxb7 Bxb7 26.Rxb7+ 1-0 Schindler,V (2010)-Seuffert,G (2095)/Bayern 1996] 10.Nxd5 [10.Be3 Qe5 11.Qxe5+ Bxe5 12.Nxd5 Nf6 13.Bf4 Bxf4 14.Rfe1+ Kf8 15.Nxf4 g5 16.Ne2 Kg7 17.h3 Rad8 18.f4 h6 19.Rad1 Rhe8 20.Kf2 Nd5 21.fxg5 hxg5 22.Ng3 Nf4 23.Rxe8 Rxe8 1/2-1/2 Kaufmann,M (2167)-Gessenich,D (1526)/IECG email 2001] 10...Bc6 11.Ne3N [11.Nc3 g6 12.Qh4 Be7 13.Qh3 Nxc3 14.bxc3 Qd7 15.Qg3 0-0-0 16.Rb1 h5 17.Re1 Bd6 18.Qh4 Qg4 19.Qh3 f5 20.Bb2 Qxh3 21.gxh3 Rhe8 22.c4 Bb4 23.Re5 Rxe5 24.Bxe5 Bc5 25.Re1 Re8 26.Kf1 h4 27.f4 Re6 28.Bc3 Kd7 29.Rxe6 Kxe6 30.Bd2 Be4 31.Ba5 c6 32.Bd2 Bd4 33.Bc1 g5 34.Bxe4 fxe4 35.fxg5 Kf5 36.Ke2 Bg1 37.Ba3 c5 38.Bc1 Bxh2 39.Be3 b6 40.a4 Bd6 41.Kf2 Be7 42.g6 Kxg6 43.Bf4 Bd8 44.Bb8 a6 45.Ke3 Kf5 46.Bd6 Bg5+ 47.Ke2 Bf4 48.Be7 Bg5 49.Bd6 Bf4 1/2-1/2 Kliesch,B-Wolf,W/DDR 1990] 11...g6 12.Qh3 Ng5 13.Qg4 Qf4 [13...Qxg4 seems to equalise but maybe Kramnik did not like 14.Nxg4 Ne6 15.Nh6 because of 15...Kf8 16.Bd2 Be5 17.Rab1 Bg7 18.Bb4+ Ke8] 14.Qxf4 Bxf4 15.Nc4 Ne6 [15...Bxc1 16.Raxc1 Ne6 17.Ne5 Bd5 18.c4 Bc6 and the queenside pawns are fractured after a capture on c6.] 16.Bxf4 Nxf4 17.Rfe1+ Kf8 18.Bf1 Bb5?! [18...Rd8 19.Rad1 Kg7 20.Ne5 Bd5 21.g3 Nh5 is pretty solid.] 19.a4 Ba6 20.b4 [20.Na5 Bxf1 21.Kxf1 Ne6 should hold because if 22.Nxb7 Rb8 23.Na5 Rxb2=] 20...Bxc4 21.Bxc4

Now Fritz has bishop against knight on an open board and much better development . This looked difficult for Kramnik who has to activate the Rh8 without allowing an incursion onto the seventh rank. 21...Rd8 22.Re4 Nh5 [22...Nd5 23.Rd1 c6 24.Red4 Ke7 25.Kf1 Nxb4 26.Re1+ Kf6 27.Rf4+ Kg5 28.Rxf7 Nxc2 29.f4+ Kh6 30.Re2 Nd4 31.Re3 Kramnik would automatically reject such lines against a computer.] 23.Rae1 Rd7 24.h3 [24.c3 looks more harmonious.] 24...Ng7 25.Re5 [25.g4 h5 26.Kg2 hxg4 27.hxg4 f5 28.gxf5 gxf5 and Black is close to equal now that both rooks are active.] 25...Nf5 26.Bb5 [26.Re8+ Kg7 27.Rxh8 Kxh8 28.Re8+ Kg7 29.Ra8 Rd4 30.Bd3 Nd6=] 26...c6 27.Bd3 Nd6 28.g4 [28.c4!? Intending c5.] 28...Kg7 29.f4 Rhd8 Now Kramnik curls up into a ball and defies the computer's attempts to break through. 30.Kg2 Nc8 31.a5 Rd4 32.R5e4 Kf8 33.Kf3 h6 34.Rxd4 Rxd4 35.Re4 Rd6 [35...Rxe4 36.Kxe4 Ke7 37.g5 hxg5 38.fxg5 Nd6+ 39.Ke5 With ideas of c4-c5 followed by rerouting the bishop to the h3-c8 diagonal.] 36.Ke3

[36.h4!?] 36...g5! Fixing white pawns on white squares and trying to secure some dark squares for his knight. 37.Rd4 Ke7! 38.c4 Rxd4 39.Kxd4 gxf4 40.Ke4 Kf6 41.Kxf4 Ne7 If Black can play b7-b6 he will be rid of a potential weakness on b7 and now he also has the possibility of Ng6-e5 when the knight is no worse than the bishop. 42.Be4 b6 43.c5 After this enside cannot be infiltrated by the white king and this helps Kramnik's defence. 43...bxc5 44.bxc5 Ng6+ 45.Ke3 [45.Bxg6 fxg6 46.h4 g5+ 47.hxg5+ hxg5+ 48.Ke4 with a blocked and therefore drawn position.] 45...Ne7 46.Kd4 Ke6 It is not quite Zugzwang because the black king can go from e6 to f6 and back. 47.Bf3 f5 further simplifying. 48.Bd1 Kf6 49.Bc2 fxg4 50.hxg4 Ke6 [50...Kg5 51.Ke5 Kxg4 52.Kd6 Nd5 53.Kxc6 Nb4+ 54.Kb7 wins.] 51.Bb1 Kf6 52.Be4 Ke6 53.Bh1 Kf6 54.Bf3 Ke6 Heroic defence from Kramnik. 1/2-1/2