Commentary for black move 43:

MAURICE ASHLEY: As we take a look at the clock it seems like Kasparov has more time than the computer does, than Deep Blue does because he has 58 minutes remaining and Deep Blue has 23 minutes remaining. That is in fact not true. The one at the bottom of the screen, the /TK-P side shows it's still in that first time control, while Garry is in the second time control, you see the two. So Garry has 58 moves remaining until move 60 while Deep Blue has in fact an hour and 23 minutes remaining on its clock. And that would be -- that will be revealed as soon as it passes the 00 mark. So plenty of time for both sides. And the game -- it's heating up. I mean a mate threat has occurred. And that suggests certain actions, definite things are beginning to occur. Garry has to be very precise in his decision-making or else he could easily mind himself just completely lost instantly.

PATRICK WOLFF: No question that white is inching forward closer and closer to victory. Inching forward, it's a long and winding road, it's not direct, black still has lots of ways to defend. But white is definitely working its way in there. It's a very, very dangerous position pour -- position for Kasparov.

MAURICE ASHLEY: It does look that way indeed. And maybe the most precise move is preventing anything with the move Kf1, against the possible perpetual check. I'm interested in Kf1 in your opinion. I'm interested in the variation you said before, Rb8 Qd7+ Kg8 Ra7 and now Bf8, and now the queen doesn't have the repet. It's not the same form of repet, although it's similar pat let's get some idea of what's going on here. Qe3. Qe6+ Kh8 Bd5. I'm just doing this to give some idea of the dangerer here to black, actually. The point of this variation is just to show what kind of danger this position holds for black. Now white is very, very close to checkmate, right? One move away. If it were white's turn, Qg8 would be checkmate. Black cannot move this bishop to allow this rook to defend because then white will capture this pawn and that will be checkmate. So black is down to his last line of defense, and his last line of defense is actually a counterattack --

MAURICE ASHLEY: Kf1, I'm sorry to interrupt you, but Kf1 has in fact been played, and Rb8 has been played.

PATRICK WOLFF: Here we go.

MAURICE ASHLEY: So it looks as if this variation might happen. It's completely critical to the analysis, the evaluation of this position, if the move Qd7+ were to be played, and if Kasparov has missed one tiny nuance, this game is over because his king is in critical danger.

YASSER SEIRAWAN: Indeed. (Audience laughter.)

MAURICE ASHLEY: Thank you for that support. Finish your point, Patrick.

YASSER SEIRAWAN:

PATRICK WOLFF: My point being, if we go all the way down here. I want to make two points. First of all, this is Kasparov's last line of defense. The last line of defense is what we call perpetual check. Continually checking the opponent's king. There's no danger of checkmate. That's why it's call perpetual check, but it goes on forever, it's perpetual, and because it's continually check, check, check, check, check, check, check, the game could be a draw. Whether or not this is perpetual check requires very, very precise analysis.

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