Round Four saw the Machine spring the first of its surprises.
It had finally forced a draw against Sherevsky in the morning session, ending the long second-round game, and now was matched against Votbinnik.
The Machine opened Pawn to King Four, Votbinnik replied Pawn to King Three.
"The French Defense, Binny's favorite," Dave muttered and they settled back for the Machine's customary four-minute wait.
Instead the Machine moved at once and punched its clock.
Sandra, studying Votbinnik through her glasses, decided that the Russian grandmaster looked just a trifle startled. Then he made his move.
Once again the Machine responded instantly.
There was a flurry of comment from the stands and a scurrying-about of officials to shush it. Meanwhile the Machine continued to make its moves at better than rapid-transit speed, although Votbinnik soon began to take rather more time on his.
The upshot was that the Machine made eleven moves before it started to take time to 'think' at all.
Sandra clamored so excitedly to Dave for an explanation that she had two officials waving at her angrily.
As soon as he dared, Dave whispered, "Great must have banked on Votbinnik playing the French—almost always does—and fed all the variations of the French into the Machine's 'memory' from MCO and maybe some other books. So long as Votbinnik stuck to a known variation of the French, why, the Machine could play from memory without analyzing at all. Then when a strange move came along—one that wasn't in its memory—only on the twelfth move yet!—the Machine went back to analyzing, only now it's taking longer and going deeper because it's got more time—six minutes a move, about. The only thing I wonder is why Great didn't have the Machine do it in the first three games. It seems so obvious."
Sandra ticketed that in her mind as a question for Doc. She slipped off to her room to write her "Don't Let a Robot Get Your Goat" article (drawing heavily on Doc's observations) and got back to the stands twenty minutes before the second time-control point. It was becoming a regular routine.
Votbinnik was a knight down—almost certainly busted, Dave explained.
"It got terrifically complicated while you were gone," he said. "A real Votbinnik position."
"Only the Machine out-binniked him," Bill finished.
Judy hummed Beethoven's "Funeral March for the Death of a Hero."
Nevertheless Votbinnik did not resign. The Machine sealed a move. Its board blacked out and Vanderhoef, with one of his assistants standing beside him to witness, privately read the move off a small indicator on the console. Tomorrow he would feed the move back into the Machine when play was resumed at the morning session.
Doc sealed a move too although he was two pawns down in his game against Grabo and looked tired to death.
"They don't give up easily, do they?" Sandra observed to Dave. "They must really love the game. Or do they hate it?"
"When you get to psychology it's all beyond me," Dave replied. "Ask me something else."
Sandra smiled. "Thank you, Dave," she said. "I will."

Come the morning session, Votbinnik played on for a dozen moves then resigned.
A little later Doc managed to draw his game with Grabo by perpetual check. He caught sight of Sandra coming down from the stands and waved to her, then made the motions of drinking.
Now he looks almost like a boy, Sandra thought as she joined him.
"Say, Doc," she asked when they had secured a table, "why is a rook worth more than a bishop?"
He darted a suspicious glance at her. "That is not your kind of question," he said sternly. "Exactly what have you been up to?"
Sandra confessed that she had asked Dave to teach her how to play chess.
"I knew those children would corrupt you," Doc said somberly. "Look, my dear, if you learn to play chess you won't be able to write your clever little articles about it. Besides, as I warned you the first day, chess is a madness. Women are ordinarily immune, but that doesn't justify you taking chances with your sanity."
"But I've kind of gotten interested, watching the tournament," Sandra objected. "At least I'd like to know how the pieces move."
"Stop!" Doc commanded. "You're already in danger. Direct your mind somewhere else. Ask me a sensible, down-to-earth journalist's question—something completely irrational!"
"Okay, why didn't Simon Great have the Machine set to play the openings fast in the first three games?"
"Hah! I think Great plays Lasker-chess in his programming. He hides his strength and tries to win no more easily than he has to, so he will have resources in reserve. The Machine loses to Lysmov and immediately starts playing more strongly—the psychological impression made on the other players by such tactics is formidable."
"But the Machine isn't ahead yet?"
"No, of course not. After four rounds Lysmov is leading the tournament with 3-1/2—1/2, meaning 3-1/2 in the win column and 1/2 in the loss column...."
"How do you half win a game of chess? Or half lose one?" Sandra interrupted.
"By drawing a game—playing to a tie. Lysmov's 3-1/2—1/2 is notational shorthand for three wins and a draw. Understand? My dear, I don't usually have to explain things to you in such detail."
"I just didn't want you to think I was learning too much about chess."
"Ho! Well, to get on with the score after four rounds, Angler and Votbinnik both have 3—1, while the Machine is bracketed at 2-1/2—1-1/2 with Jal. But the Machine has created an impression of stre............