World chess champion Garry Kasparov and the IBM supercomputer Deep Blue played their second consecutive draw Wednesday in New York City. The $1.1-million match remains tied at 2-2. The final two games are scheduled Saturday and Sunday.
The result of one win apiece and two draws duplicates the course of the 1996 match between Kasparov and a slower version of Deep Blue. Kasparov finished with two more victories to win that match, 4-2.
In Wednesday's game, Kasparov played Black and adopted the Prybl Defense, a bizarre opening invented only a few years ago. Kasparov has repeatedly tried to surprise Deep Blue with his choice of opening so that the machine cannot play a long series of programmed moves. Nevertheless, Deep Blue secured an advantage in the early stages.
At move 16, Kasparov weakened his pawn structure in a bid for counter-play. Probably he already envisioned his excellent sacrifice of a pawn at move 20, which threw Deep Blue on to the defense. Most computer programs rate an extra pawn very highly, making them susceptible to sacrifices with long-range payoffs. Deep Blue returned the extra pawn at move 37, reaching an end game with nearly even chances. After five hours of play, Kasparov offered the draw, and Deep Blue's programmers accepted at once.
"I felt I was winning, I thought the pawn sacrifice was good, but I missed something in my time trouble," said Kasparov, who had to play moves 27-40 in only 21 minutes because he had used too much time on earlier moves.
The two combatants are playing on the 35th floor of the Equitable Building, a Manhattan skyscraper. There is a separate press room on the 50th floor to serve the 300 journalists covering the match. Chess fans watch the action on three large video screens in the sold-out basement auditorium. The moves are transmitted over the Internet at IBM's Web site (http://www.chess.ibm.com) and many chess servers.
Kasparov's last chance with the White pieces comes Saturday at noon PDT. He must win another game to collect the $700,000 winner's share of the purse. If the match finishes in a 3-3 tie, Kasparov would receive $550,000, and the Deep Blue team would split the other $550,000. The money is provided by IBM, which considers the match a research project.
Here are the moves of Wednesday's game.
Deep Blue -- Kasparov #4: 1 e4 c6 2 d4 d6 3 Nf3 Nf6 4 Nc3 Bg4 5 h3 Bh5 6 Bd3 e6 7 Qe2 d5 8 Bg5 Be7 9 e5 Nfd7 10 Bxe7 Qxe7 11 g4 Bg6 12 Bxg6 hxg6 13 h4 Na6 14 0-0-0 0-0-0 15 Rdg1 Nc7 16 Kb1 f6 17 exf6 Qxf6 18 Rg3 Rde8 19 Re1 Rhf8 20 Nd1 e5 21 dxe5 Qf4 22 a3 Ne6 23 Nc3 Ndc5 24 b4 Nd7 25 Qd3 Qf7 26 b5 Ndc5 27 Qe3 Qf4 28 bxc6 bxc6 29 Rd1 Kc7 30 Ka1 Qxe3 31 fxe3 Rf7 32 Rh3 Ref8 33 Nd4 Rf2 34 Rb1 Rg2 35 Nce2 Rxg4 36 Nxe6 Nxe6 37 Nd4 Nxd4 38 exd4 Rxd4 39 Rg1 Rc4 40 Rxg6 Rxc2 41 Rxg7+ Kb6 42 Rb3+ Kc5 43 Rxa7 Rf1+ 44 Rb1 Rff2 45 Rb4 Rc1+ 46 Rb1 Rcc2 47 Rb4 Rc1+ 48 Rb1 Rxb1+ 49 Kxb1 Re2 50 Re7 Rh2 51 Rh7 Kc4 52 Rc7 c5 53 e6 Rxh4 54 e7 Re4 55 a4 Kb3 56 Kc1, Drawn.