Many were puzzled at the timing of Anatoly Karpov's resignation to Gary Kasparov in the final game of the world chess championship Saturday. Here is a more detailed analysis of the situation.
In the final position (Diagram 1), Karpov's situation is desperate: His king is totally immobilized; his knight is under attack, pinning his queen down for the knight's defense; and the knight cannot be moved without the immediate loss of at least one pawn. It is black's move, and the only choices practically available to him are meaningless queen moves, such as 64. ... Qc8 or 64. ... Qa3, which keep the knight protected. By proper timing, waiting until the black queen is out of position, white should be able to take the pawn on g6 without losing his own on e5. But even if the e5 pawn falls, white can force a win.
First, he lines up his bishop on the g6 pawn, perhaps with 65. Bf3 and 66. Be4. Then, after 67. Bxg6, Nxg6; 68. Qxg6 (see Diagram 2), white can force a queen exchange and reach a theoretically won pawn endgame. For example: 68. ... Qxe5; 69. Qh6ch, Kg8; 70. Qg5ch, Qxg5; 71. hxg5. White can then defend the passed g-pawn with his f-pawn and use his king as the situation dictates.
A likely continuation might be: 71. ... Kg7; 72. f4, Kg6; 73. Kf3, e5; 74. Ke4. Then, if 74. ... exf4; 75. gxf4, and white can bring his king back to stop the now-passed black h-pawn while black's king is tied down, unable to attack the white pawn on f4 because that would give the white pawn on g5 a clear shot at becoming a queen.
Grandmaster Lubomir Kavalek contributed to this report.