Bulgaria's Veselin Topalov and England's Michael Adams, the two top-rated players at the FIDE World Championship in Tripoli, Libya, made it to the quarterfinals yesterday. But two other superstars are gone on one-move blunders. Ukraine's Vassily Ivanchuk, a current European champion, was knocked out after he dropped a pawn and lost to the Uzbek Rustam Kasimdzhanov. And the biggest mistake of the championship was committed by England's Nigel Short, who hung a full rook in a winning position to Michal Krasenkow of Poland.

The Last American

The young Hikaru Nakamura made it among the last 16 players, defeating Alexei Alexandrov of Bulgaria and the Russians Sergei Volkov and Alexander Lastin, all much higher rated grandmasters. He was the last remaining American in the championship before being eliminated yesterday by Adams. Still, he won $22,000 in prize money -- not bad for a 16-year-old.

Nakamura's win against Lastin in the Meran defense was based on sound opening preparation, inventive middlegame and solid endgame play.

Nakamura-Lastin

1.d4 d5 2.c4 c6 3.Nc3 e6 4.Nf3 Nf6 5.e3 Nbd7 6.Bd3 dxc4 7.Bxc4 b5 8.Bd3 Bb7 9.0-0 a6 10.e4 c5 11.d5 (The sharp Reynolds variation of the Meran defense.) 11...Qc7 12.dxe6 fxe6 13.Bc2 c4 14.Nd4 Nc5 15.Be3 (French grandmaster Joel Lautier's plan, threatening to undermine black's queenside with 16.b4.) 15...0-0-0 16.Qe2 e5 (After 16...Bd6 Lautier planned 17.f4 e5 18.Ndxb5! axb5 19.Nxb5 Qb6 20.Nxd6+ Qxd6 21.fxe5 Qxe5 22.Rf5 and white wins.) 17.Nf3 Nd3!? (Plugging the knight in is the latest trend. In the game Lautier-Gelfand, Amsterdam 1996, black took the pawn 17...Ncxe4?, but after 18.Nxe4 Nxe4 19.a4! Nc5 20.axb5 axb5 21.b3! white was able to dismantle black's queenside and won in 32 moves. Lautier later suggested 17...b4!?, but after 18.Nd5! Nxd5 19.exd5 Bxd5 20.Rfd1! e4 the exchange sacrifice 21.Rxd5! Rxd5 22.Qxc4 leaves white with a powerful pressure.)

18.a4! (Nakamura's new idea, loosening black's queenside pawn chain with a plan to undermine the knight on d3. The immediate 18.b3 can be met by 18...Bb4!) 18...b4 19.Nd5! Nxd5 (After 19...Bxd5?! 20.exd5 Rxd5 21.b3! is strong.) 20.exd5 e4 (Better is 20...Rxd5 21.b3 e4 22.Nd2 Bd6! with chances to equalize.) 21.Nd2 b3? (Forcing the following exchange, but leaving his pawns weak. Black had to try 21...Bd6.) 22.Bxd3 cxd3 (After 22...exd3 23.Qg4+ Kb8 24.Nxc4, threatening 25.Bf4, black is in trouble.) 23.Qg4+ Qd7 (Hoping for 24.Qxe4 Qxd5 and black is fine.)

24.Qf4! (Nakamura's play with the queen is impressive. The zigzag maneuver lets him gobble the e-pawn at the right moment. It is stronger than 24.Rac1+ Kb8 25.Qxe4 Bxd5 26.Qxd3 Qxa4 and black lives.) 24...Bxd5 25.Rfc1+ Kb7 26.Qe5! (The queen move hampers black's development of the kingside. After 26.Nxe4 Bxe4 27.Qxe4 Qd5 black may survive.) 26...Be7 (Black has to be humble. After 26...Bc6 comes 27.Rc3!; and 26...Bb4? is met by 27.Qd4!) 27.Nxe4 Rhe8 28.Qd4 Ka8 (Now after 29.Qxd3 Qb7 black jumps out, but Nakamura has a surprise up his sleeve.)

29.Nd6! (A beautiful interference, forcing a clearly better endgame.) 29...Bxd6 (The only move. After 29...Bxg2 30.Nxe8 Qxd4 31.Bxd4 Bh3 32.Nc7+ Kb7 33.Rc4 Bd6 34.Rc3 Bxc7 35.Rxb3+ Ka8 36.Rxd3 white prevails. On 29...Bc6? 30.Rxc6! wins.) 30.Qxd5+ Qb7 31.Qxb7+ Kxb7 32.Rc3 Bb4 33.Rxb3 a5 34.Kf1 d2 (The passed d-pawn gives black some counterplay. Would Nakamura be able to encircle it and win it?) 35.Rd1 Kc6?! (Defending against the threat 36.Rxd2, the black king goes the wrong way out of the pin. Better was 35...Ka6 to keep the c-file open. The idea becomes clear after 36.Ke2 Re6 37.Rd3 Rxd3 38.Kxd3 Rd6+ and now after either 39.Kc2 Rc6+! [the point!] 40.Kb3 Rd6; or 39.Ke2 Re6 black can make it difficult for white to win the d-pawn.)

36.Ke2 Kd5 37.Rd3+ Kc6 38.b3! (Much better than 38.Rxd8 Rxd8 39.Bxd2 Bxd2 40.Rxd2 Rb8! 41.Kd3 Rb4; black still has some hopes to draw the rook endgame.) 38...Rb8 39.Rd4 Re5 40.Kd3 Bc5 41.Rc4 Rxb3+ 42.Kxd2 (White is only a pawn up, but the black king can't break the pin unharmed.) 42...Rb2+ 43.Kc3 Rb4 44.Rdd4! (Maintaining the pin. Black will soon run out of good moves.) 44...h5 (After 44...Kb7 45.Rd7+ Kc6 46.Rxg7 wins.) 45.g3 g5 46.h4 g4 47.Rf4 Rxc4+ 48.Rxc4 (The upcoming pawn endgame is easily won.) 48...Kb6 49.Rxc5 Rxc5+ 50.Kd3! Kc6 51.Bxc5 Kxc5 52.Ke3 (After 52...Kb4 53.f4 gxf3 54.g4! hxg4 55.h5 and white comes first.) Black resigns.

Browne wins

Walter Browne won the Virginia Open, a five-round Swiss event, June 20 in Springfield. The six-time U.S. champion scored 41/2 points. Andrew Briscow triumphed in the amateur section, winning all five games.

On June 17 Browne gave a simultaneous exhibition at the Arlington Chess Club, winning 19 games, drawing three and losing to Darwin Li, a 10-year-old who attends Forest Edge Elementary School in Reston. Solution to today's problem by Pal Benko (White: Kg4,Rh5,Bd4,Bg8,Ng2,P:e2; Black: Kg6,Bg5,P:e4,h6): 1.Bh8! e3 2.Kf3! Kxh5 (Or 2...Kf5 3.Nh4 mate; or 2...Bf6 3.Nf4 mate.) 3.Bf7 mate.

White mates in three moves.