Grandmaster Krishnan Sasikiran marched ahead with his tactical brilliance, turning tables on GM Bruzon Lazaro of Cuba in the fourth round of the 18th North Sea Cup International chess tournament in Esbjerg, Denmark.

Sasikiran took his tally to three points out of a possible four and now shares the lead with GM Luke McShane of England, who defeated GM Michal Krasenkow of Poland in a keenly-contested game.

Half a point adrift of the leaders are top seed GM Alexey Dreev of Russia and Curt Hansen of Denmark. Of the two, Dreev was involved in a nonchalant draw with Lenier Dominiguez of Cuba while Hansen used his positional prowess to outclass former world junior girls champion Koneru Humpy.

Denmark's Lars Schandorff, Hastings champion Peter Heine Nielsen (Den) and Lazaro share the fifth spot on a 50 per cent score while Krasenkow and Lenier were relegated to joint eighth spot having just 1.5 points from the four games played so far.

Humpy's bad patch continued as she suffered her fourth loss on the trot and was yet to open her account even at the half-way stage of this 10-player, nine-round tournament.

Sasikiran was lucky as Lazaro blundered away a clearly superior position. The players fought the initial phase in an  irregular opening that gave Sasikiran dynamic equilibrium with black pieces.

Lazaro was quick to pounce on a middle game error by the Indian stalwart that gave him a firm bind and spatial advatgae. Sasikiran worked out his counterplay in the final stages of the first time control when he sacrificed a pawn in  the center and caught Lazaro's king unattended by the supporting force.

On the 42nd move Lazaro resigned when he was unable to cope with irresistible threats.

Humpy seems woefully out-of-form and the recovery for the youngest GM of the country seems highly unlikely in this tournament.

Hansen took his chances in the middle game arising out of an unorthodox Queen pawn game and was rewarded as Humpy fell in to a positional trap that left her light square Bishop crippled.

Hansen seized control of the dark squares with his rooks soon after and a tactical sortie netted him a couple of pawns on the 23rd move itself. Soon Humpy's king also came under firing range and the game ended in just 29 moves.

Krasenkow gave a demonstration of his positional acumen by giving his queen for three minor pieces and a pawn against McShane, who played black.

However, in the complex middle game that ensued, the Polish player missed the thread and subsequent exchanges led to a very loose position for him on both flanks. McShane wrapped up the issue in 42 moves.

Dreev was up against a solid Dominiguez. The Russian nevertheless managed to turn the heat on in the endgame. But  precise defensive moves by the Dane steered the game to a peace result after 51 moves.

Schandorff and Nielsen played a draw in just 26 moves of a Queen pawn game where the former played white.

Results Round 4: Bruzon Lazaro (2, Cub) lost to K Sasikiran (3); Michal Krasenkow (1.5, Pol) lost to Luke McShane (3, Eng); Curt Hansen (2.5, Den) beat Koneru Humpy (0); Lenier Dominiguez (2, Cub) drew Alexey Dreev (2.5, Rus); Lars Schandorff (2, Den) drew Peter Heine Nielsen (2, Den).

Moves:

B Lazaro v/s K Sasikiran: 1. Nf3 Nf6 2. c4 g6 3. b4 Bg7 4. Bb2 d6 5. g3 O-O 6. Bg2 e5 7. O-O Re8 8. d3 Nh5 9. Nc3 f5 10. Nd2 Kh8 11. e3 Nd7 12. Qc2 Ndf6 13. b5 a6 14. a4 Rb8 15. Ba3 a5 16. Nd5 b6 17. Rae1 g5 18. Bb2 Be6 19. Nxf6 Bxf6 20. d4 Ng7 21. dxe5 dxe5 22. Rd1 Qe7 23. Bc6 Red8 24. Qc3 Nh5 25. e4 f4 26. Nf3 Bh3 27. Rfe1 Kg7 28. Rd5 Rxd5 29. cxd5 Rd8 30. Nd2 Kh6 31. Nc4 Qg7 32. Qf3 fxg3 33. fxg3 Rf8 34. Qe2 Be7 35. Nxe5 Bc5+ 36. Kh1 Qe7 37. Nd3 Bf1 38. Qd2 Bxd3 39. Qxd3 Rf2 40. Bc1 Qf7 41. e5 Ra2 white resigned.

Curt Hansen v/s K Humpy: 1. Nf3 d5 2. d4 Nf6 3. c4 e6 4. Nc3 Nbd7 5. Bf4 dxc4 6. e3 Nd5 7. Bxc4 Nxf4 8. exf4 Nb6 10. O-O O-O 11. Re1 c6 12. Qe2 Nd5 13. Nxd5 cxd5 14. Rad1 Bf6 15. Ne5 Bd7 16. g3 Bxe5 17. dxe5 Bc6 18. Rd4 f5 19. exf6 Rxf6 20. Qd2 Qd6 21. Re5 Raf8 22. h4 Bd7 23. Bxd5 exd5 24. Rdxd5 Qa6 25. Rxd7 Qxa2 26. Rxb7 Qb1+ 27. Kg2 Rb6 28. Qd5+ Kh8 29. Qf7 9. Bb3 Be7 black resigned.