Computerized chess programs have now beaten the strongest male and female players in the world, Garry Kasparov and Judit Polgar, and have returned to what computer chess experts consider truly important: the battle of the machines against each other. It is more a volatile struggle than the battles of mere flesh and blood. At the 9th World Computer Chess Championship last month in Paderborn, Germany, a relatively unknown German program, named Shredder, won the title on a tie-break over an American entry, Ferret, both scoring 5.5 points in 7 games.

Last April, the defending champion, Fritz, developed in Germany by Dutch programmer Frans Morsch, beat Judit Polgar. But in championship competition against 29 programs from 11 countries, Fritz could only tie for third place with another American program, Cilkchess, half a point behind the winners.

The highly regarded Israeli program Junior scored 4.5 points, but played one of the most brilliant games against a powerful Austrian program, Nimzo. In the Petrosian system of the Queen's Indian, Junior made an intuitive knight sacrifice without seeing a clear end. Eventually, the Israeli program found the way to the black king.

Junior-Nimzo 1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.a3 Bb7 5.Nc3 d5 6.Bg5 dxc4 7.e4 Be7 8.Bxf6 (A new choice of the Dutch GM Loek van Wely, who has previously played 8.Qc2 without success.) 8...Bxf6 9.Bxc4 0-0 10.e5 Be7 11.0-0 c5 12.d5 exd5 13.Nxd5! (Stronger than 13.Bxd5 played in the game Van Wely-Korchnoi, Wijk aan Zee 1997.) 13...Nc6 14.Qd3 b5 15.Ba2! (Not 15.Bxb5? Nxe5! and black frees himself.) 15...c4 16.Qe4 Bc5 (Black is ready to stop the pressure. For example after 17.Rad1 he would have played 17...Nd4 with the idea 18.Nf6+ Qxf6! But white has something else up his sleeve.)

17.Nf6+! (An intuitive sacrifice leading to a draw by force. But can white scramble for more? ) 17...gxf6 18.Bb1 Re8 19.Qxh7+ Kf8 20.Qh6+ Ke7 (Not 20...Kg8 21.Bh7+ Kh8 22.Bg6+ Kg8 23.Qh7+ Kf8 24.Qxf7 mate.) 21.Qxf6+ Kf8 22.Qh6+ Ke7 23.Be4!? (A winning attempt, rejecting a draw after 23.Qf6+. Another way to open up the game was the direct 23.e6, for example 23...Qd5 24.exf7 Rh8 25.Re1+ Kd7 26.Qg7 Raf8 27.Be4 with a powerful pressure.) 23...Qb6 (White would have a mighty attack along the central files after 23...Rc8 24.Rad1 Qc7 25.Nh4 Rg8 26.Nf5+ Ke8 27.Nd6+ Bxd6 28.exd6 Qd7 29.Rfe1 winning.)

24.e6!? (The pawn clears the path to the king.) 24...Rad8 (Clearly after 24...fxe6 25.Qg7+ Kd8 26.Rad1+ wins, but other defenses do not work either. For example 24...Nd8 25.Rad1 Bd6 26.Bxb7 Nxb7 27.Rfe1 Kd8 28.exf7 Rxe1+ 29.Rxe1 Kd7 30.Qe6+ Kc7 31. Qe8 Rd8 32.Re7+ Bxe7 33.Qxe7+ Kc8 34.f8Q winning; or 24...Rf8 25.Qg5+ Ke8 26.exf7+ Rxf7 27.Bg6 Ne7 28.Bxf7+ Kxf7 29.Ne5+ Ke6 30.Rae1 Kd6 31.Nxc4+! bxc4 32.Qxe7+ Kc6 33. Re6+ and black loses the queen.) 25.exf7 Rh8 26.Qg7 Rhf8 (After 26...Rdf8 comes simply 27.Rad1.) 27.Bf5! Rxf7 (After 27...Rd5 28.Rfe1+ Kd8 29.Rad1 the king does not escape, e.g. 29...Rxd1 30.Rxd1+ Kc7 31.Qg3+ wins.) 28.Rfe1+ Black resigned.

In an exhibition match the top five computers from the championship held their own against five grandmasters. Three games were drawn and the Armenian GM Rafael Vaganian won against Ferret. But Ivan Sokolov, a Bosnian grandmaster, who inflicted the only defeat on Garry Kasparov this year at the Wijk aan Zee in January, was demolished by Fritz in just 22 moves of the Spanish game.

Fritz - Sokolov

1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4.0-0 Nxe4 5.d4 Nd6 6.Bxc6 dxc6 7.dxe5 Nf5 8.Qxd8+ Kxd8 (The exchange of queens in the Berlin defense gives black chances to equalize. White usually aims to set up in motion the pawn majority on the kingside, but this game is a different story.) 9.Nc3 Ke8 10.Rd1 a5 11.h3 Bc5?! 12.g4! Ne7?! (Losing by force, but 12...Nh6 looks ugly.) 13.Ne4 Ba7 (Now comes the shocker.)

14.Bh6!! (Developing with gusto, white gets the winning edge.) 14...f5 (Black cannot accept the piece. After 14...gxh6 15.Nf6+ Kf8 16.Rd8+ Kg7 17.Nh5+ Kg6 18.Rxh8 wins. Neither can he protect the pawn with 14...Rg8, because of 15.Bxg7! Rxg7 16.Nf6+ Kf8 17.Rd8 mate. And 14...Nf5 makes no difference after 15.Bg5! Ne7 16.Bf6!) 15.exf6 gxh6 16.Re1! (It was possible to collect the knight on e7, but the rook move increases the pressure.) 16...Ng6 (Black cannot keep the piece with 16...Nd5, because of 17.c4! Nf4 18.Nd6+ Kd7 19.Rad1! with a winning attack, for example 19...cxd6 20.Re7+ Kd8 21.Rxd6+ Bd7 22.Rdxd7+ Kc8 23.Rc7+ Kb8 [Or 23...Kd8 24.f7 mates soon] 24.Rxb7+ Kc8 25. Ne5 with a mating attack.) 17.Nd6+ Kd7 18.Nf7 Bc5 (The other way to avoid mate 18...c5 is not helping either after 19.Nxh8 Nxh8 20.Rad1+ Kc6 21.Ne5+ Kb5 22.Rd8, winning.) 19.Rad1+ Bd6 20.Nxh8 Nxh8 21.Re7+ Kd8 22.Ne5 (Black is completely tied up and has no defense to 23.Rxh7.) Black resigned.

Solution to today's study by Josef Hasek (White: Ka1,Ba3,P:g6,h6; Black: Kh8,Nd1, P:a2,b3,g7): 1.Bb2! Nxb2 2.h7! Nd3 stalemate.