The third round of the 2009 Kalkota Open GM Chess Tournament saw Indian GM Pancanathan Magesh Chandran beat Uzbek - GM Rauf Mamedov in a two knight vs a pawn ending. As generally known, endgame with two knight + plus king vs king is a draw because a pair of knight can't mate a lone king by force because a stalemate situation would arise when the defender king is stuck near a corner.
However if the defending side has a pawn ( the damned pawn according to GM Karsten Muller! ) , and the pawn is block (by one of the white knights) on a square no further forward than the line a4-b6-c5-d4-e4-f5-g6-h4 which is call The Troitzky Line, then the stronger side can win the resulting endgame (and similarly in reverse for Black), no matter where the other pieces are placed.
The winning method is the superior side block the pawn with his knight and the another knight- with the help of the king force the defending king into a corner. After that the knight who perform the blockading task move from his duty and go towards the defending king to deliver mate !
ThisTroitsky Line was invented by a Russian Theoritician - Troitsky. He discovered the following line.
Let see the game.
GM Rauf, Mamedov vs. GM Magesh Chandran, Panchanathan
4th Kolkata Open Grandmaster Chess Tournament, 3.9.09, Round 3
White to move
As you can see from diagram below, white (damned) c-pawn is far under the troitzky line which is in this case the c5 square. So black should win by blockding the pawn with his knightat c6.
48. Kb4 Ke5 49. c4 Nf5 50. Kb5 Nd4+ 51. Kb4 N8c6+ 52. Kc3 Kd6 53. c5+ Kd5 Black c-pawn is safely block on c5, now black king and knight will force white's king into the corner. 54. Kd3 Ke5 55. Ke3 Kf5 56. Kd3 Kf4 57. Kc3 Ke4 58. Kc4 Nf3 59. Kc3 Nfe5 60. Kd2 Kf3 61. Kc2 Ke2 62. Kc3 Ke3 63. Kc2 Nf3 64. Kc3 Nd2 65. Kc2 Ne4 66. Kd1 Kf2 67. Kc2 Ke2 68. Kc1 Nf6 69. Kc2 Nd5 70. Kb3 Kd3 71. Kb2 Ndb4 72. Kc1 Ke2 73. Kb2 Kd2 74. Kb3 Kd3 75. Kb2 Nc2 76. Kc1 Ne3 77. Kb2 Kc4 78. Ka3 Nd1 79. Ka2 Kc3 80. Ka3 Nb2 81. Ka2 Nc4 82. Kb1 Kd2 83. Ka2 Kc2 84. Ka1 84...N6a5 This win by force. However a quicker win is 84...Nb4! 85.c6 Nd2 86.c7 Nb3++ checkmate 85. c6 Nb3+ 0-1 White resign because he will be checkmated after 86. Ka2 Nc1+ 87. Ka1 Nd2 88. c7 Ndb3#