Chess blindness? Is that what caused Gary Kasparov, the world champion, to blunder in the seventh game in his world title match with Anatole Karpov?

Many top players have suffered chess blindness and given a piece away. "There was no intimation of the awful blunder that the champion was about to make at his 27th turn," Robert Byrne, chess editor of the New York Times and a winner of many championships, wrote of Kasparov's seventh game loss."He was not short of time, and the problems he faced were not nearly enough to elicit a gross mistake."

Aleksandr Roshal, the chess reporter for Izvestia and Ogonyok, said, "When a great player does that sort of thing, the reason is bad nerves. The tension in a championship match is unbelievably severe. No one entirely escapes it.

"Losing in such an ignoble way could mean even more than the loss of an important point. It makes a mockery of Kasparov's ambitions. He said before the match began that he wanted to prove the difference between him and Karpov was greater than had been manifest in their previous four matches. Now he is stuck with embarrassment as well as chagrin."

The accompanying position chart shows the blunder after 27 . . . Qa5.

The disaster occurred at 27 . . . Qa5? which elicited cries of "That's a blunder" from the former world champions Boris Spassky and Mikhail Tal and grandmaster Ljubomir Ljubojevic.

Karpov's reply, 28 Nd5! put his finger on the trouble - Black's queen and f6 bishop were simultaneously attacked and damage was unavoidable.

As expected Kasparov resigned the game after the time limit and 43 moves were reached.

The champion sent a note of his decision to chief referee Geurt Gijssen at 12:15 p.m. The contest then stood at 31/2-31/2.

Games 8, 9, and 10 are scheduled to be played this week, and the results have been as of deadline time:

Game 8 and Game 9 are draws, the score standing at 41/2-41/2.

Game 10 is to be played Friday night.

A Manhattan party with famous people and chess masters was held last week during Game 6 and Robert D. McFadden attended and reported:

There was little of the cold technical stuff of Bg3 or Qe7.

Instead they scrutinized the players' faces on a television monitor, followed the moves on a demonstration board and spoke, sometimes quite passionately, of character and suffering, of courage and cruel egos, of the capacity to sense - and to act upon - life's crucial moments.

"Watch their faces," Boris Spassky, the Soviet grandmaster and former world champion, told the crowd.

A puzzled fan said the players were not even looking at each other.

"It is not necessary for them to look at each other," Spassky said. "They feel each other. They have a deep, deep knowledge of each other. They know each other like a man and woman who have been married for 25 years."

"In Russia," Mr. Spassky said, "there is a rule that while the game is on, the players may leave the board, even the room, but they may not speak to anyone or consult reference materials.

"They are also forbidden to use even a small book in the toilet," Mr. Spassky said to a wave of laughter, "like some grandmasters I know." (Shades of some bygone local tournaments!)

As things progressed, the players were left with bishops of opposite color. At the start, each side has two bishops one on black and one on white diagonal lines. When each side has only one bishop on the opposite color, "The remaining bishops never meet on the same paths, they pass like ships in the night. Or like people in marriage," Spassky said.

"Kasparov is a very rare player," he said. "He has a sense of the crucial moment. Karpov is more like a computer; he likes to collect small advantages. He has no sense of the crucial moment."

Everyone followed Spassky's eyes to the monitor and Karpov's image.

"That," Spassky said, "is not a happy face."

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