Calcutta, Feb. 9 :     Gregory Kaidanov of USA emerged sole leader after the fourth round of the 11th Goodricke International Open Chess tournament at Alekhine Chess Club today. Kaidanov got the better of Sriram Jha in a marathon battle lasting seven hours and nearly 90 moves. Kaidanov (4 points), is followed by four players at 3.5 - Viktor Korchnoi, Tejas Bakre, K. Sasikiran and Koneru Humpy. Meanwhile, Sandipan Chanda continued his impressive run with a draw against GM Alexander Goloshapov from an inferior position to take his tally to 3. In a semi-Slav set up Kaidanov, playing black, obtained a superior position from the opening and went into a Rook and Knight vs Rook and Knight ending a pawn up. But the conclusion posed some technical problems which Kaidanov solved in textbook fashion to win in a long ending. On the second board, Korchnoi got the better of Suvrajit Saha in a Queen's Gambit Declined. Korchnoi obtained a passed pawn in the centre and then broke open Saha's Kingside after which he was forced to resign. Sandipan Chanda once more opted for his favourite Sicilian defence but landed up in a difficult ending where he had a bad Bishop and a Rook for Alexander Goloshchapov's Rook and Bishop. But, Sandipan defended accurately to thwart Goloshchapov's winning attempts and forced a draw in 63 moves. National champion and double GM norm holder Sasikiran had little difficulty in disposing off Jayant Gokhale with the black side of the King's Indian. Sasikiran gave up his Queen for three pieces in the middle game and then combined his pieces to weave a mating net around Gokhale's King. Humpy played yet another impressive positional game to jump into the joint second spot with a win over S. Satyapragyan. In a Reti opening, Humpy exploited the pawn weakness of Satyapragyan on the Queenside and went into a double Rook ending with an outside passed pawn which proved decisive. World championship finalist Vladimir Akopian of Armenia survived a scare against IM Shanker Roy of Bengal. Akopian opened with the Owen's defence (e4 b6) in reply to Shanker's Kingpawn opening. The game later took the character of a French defence where Shanker had space advantage on the Kingside. Shanker broke open Akopian's Kingside but lost a Rook in severe time pressure. The resulting endgame posed some problems for Akopian as his King was exposed. Akopian finally managed to win after an exchange of Queens. Surya Sekhar Ganguly of Goodricke National Chess Academy held GM Pavel Blatny to a draw with black pieces in a Reti opening. Surya had the better chances in a Rook and pawn endgame but squandered his opportunities under time pressure. National sub-junior champion Saptarshi Roy, also of GNCA, outwitted IM Reefat Bin Sattar of Bangladesh to take his tally to 2. IMPORTANT RESULTS Sriram Jha (3) lost to Gregory Kaidanov (4); Viktor Korchnoi (3.5) bt Suvrajit Saha (3); Alexander Goloshapov (3) drew with Sandipan Chanda (3); Aarthie Ramaswamy (2.5) bt Tejas Bakre (3.5); Koneru Humpy (3.5) bt S Satyapragyan (2.5); Shanker Roy (2) lost to Vladimir Akopian (3); Anup Deshmukh (2) lost to Peng Xiaomin (3); Evgeny Vladimirov (3) bt V. Koshy (2); G. Singh (2.5) drew with Maxim Sorokin (2.5); Jozsef Horvath (3) bt N K Mishra (2); Abhijit Kunte (3) bt Rahul Shetty (2); Arun Vaidya (2) lost to Zia-ur Rahman (3); G B Prakash (3) bt N Neelakantan (2); V Saravanan (2) drew Ildar Ibragimov (2); Andrew Webster (1.5) lost to Viorel Iordachescu (2.5); P Konguvel (1.5) lost to Bogdan Lalic (2.5); P. Mithrakanth (1.5) lost to Leonid Yurtaev (2.5); P D S Girinath (2) drew with Tahir Vakhidov (2); Mathies Roeder (2) drew with N S Babu (2); R M Dongre (1.5) lost to Dao Thien Hai (2.5). BENGAL PLAYERS Pavel Blatny (1.5) drew with S S Ganguly (1.5); Saptarshi Roy (2) bt Reefat Bin Sattar (1); C S Gokhale (2) bt Saheli Dhar Barua (1); Roktim Bandyopadhyay (2) bt Collas Didier (1); Azer Mirzoev (1.5) bt Laltu Chatterjee (0.5); Vishal Sareen (0.5) drew with Dipanjan Das (0.5).