I wouldn't call move 5 a mistake. It's a line many grandmasters choose. Black's move 7 is a mistake, even though it is not "silly". Kasparov makes the mistake because he has a finite human memory and forgets, in the heat of the moment, a specific refutation that is in opening books. Deep Blue takes advantage of his lapse because it has an effectively infinite computer memory and follows the refutation that's in its opening books. This game precisely illustrates how opening books are important, how GMs and computers do use them to reach stronger rather than weaker positions, and how having a larger and deeper opening book is a real advantage.
Ah! I am sorry, wrong figure, I mean move 7 not 5 in my last post.
You claimed it is impossible for a grandmaster to make a mistake and play a bad opening, but this game proves you are wrong.
No. I am not wrong! Particularly when you intend to prove that according to the example you have quoted.
Remember, it is the article that said Kasparov has made a mistake in choosing that move, did Kasparov himself admit that? I repeat, that move is arguably a wrong move!
1. The wrong move 7th (as claimed by you) is not WRONG. It is simply not the best move because there is a better move (to replace it) and according to the article, the GM has play with that better move in two other matches earlier.
2. The reason why I say it is not an absolute bad openning move is, if play against another program (not deep blue) or when play against a human player, Kasparov might still win at the end. Further more, as you can find in the article, Kasparov made further mistake after the "openning phase" (that is when deep blue no more using an openning library), that again means, move no7. is arguably the sole reason that cause him to loss.
3. Let me ask this, say if Kasparov win the match at the end simply because Deep Blue is weak after it start thinking instead of using the openning library, would you still call that move a WRONG move?
4. My point is, you can only claim a move is wrong in the openning stage, if it will absolutely lead you to a lossing end and there isn't any chance at all for you to change the result if your opponent follow strictly a serial of known moves. In your example, that match is obviously not one that fulfill this condition.
I don't mean to insist on "I am not wrong"
It is obvious, openning library only serves "to save time" (for few initial moves) which otherwise a computer program will spend quite an amout of time yet still arrive at the same move (again and again in different matches when come to the same state). It is definitely not a crucial part that make a good AI. It doesn't even need logical calculation.
You and the other MR. are over-emphasizing its role! that is something I can't keep myself quiet for you are misleading others...