Author: Albert Silver
Date: 16:03:21 01/25/02
Go up one level in this thread
On January 25, 2002 at 18:31:10, Dann Corbit wrote:
>>There are two things I think you aren't
>>appreciating: first is Kasparov's non-propensity to make fatal mistakes. The key
>>word there is fatal. You are presuming that not only will the perfect player
>>will have forced winning sequences at hand at every move, but also that Kasparov
>>will forcibly make a fatal mistake. I think you are very strongly mistaken about
>>the number of non-losing moves. In many quiet positions the chances of him or
>>another player of his knowledge to make a fatal blunder is _extremely_ low IMHO.
>
>In this case, a blunder is making an imprecise move that costs you a pawn 30
>plies later and the game 100 full moves later. I don't think Kasparov (or any
>of the others) can see it.
Sometimes even being up a bishop and a pawn isn't enough, or a queen versus a
rook+pawn, etc. The ways to not lose are many times many.
Ok, let me put it differently. Let's say that in a given position there are 35
possible moves, of which 32 are forcibly losing (and I'm being ridiculously
harsh IMO).
20 lose material right away. The chance of a top player playing them is somewhat
slim.
7 lose at a depth of 10-15 moves (by this I mean that the poor human will
recognize they are lost 10 moves later). The 10-15 move ones are positional
blunders (or very deep tactics of course). Most likely the top player will avoid
these too, though their chances rise somewhat. These are moves like an illogical
h4 that may take time to exploit, but can definitely be forced to a win.
And 5 at 30 moves. The 30 move ones are what we would call positional errors
(VERY deep tactical mistakes) that can also be exploited but the road to a
forced win is very narrow.
And finally you have a miserable 3 moves that don't lose forcibly. I don't think
that it is so hard for a world-class player to hit on one of these non-losing
moves. Usually they are quite logical to boot, though the reasons the imperfect
human will give (occupies the column, development, control over e5 square, etc.)
are very different from that of the perfect player (Perfect DB says that Re1,
Bd2 and Qe1 are 0.00). You present this as though the non-losing moves are not
only extremely few, but impossibly hard to find (i.e. must look illogical
according to our understanding of the game). I think otherwise. I don't think
playing perfectly will change this either and believe this about the game of
chess as an absolute. I think perfect play from both sides would lead to a draw,
and also believe that the number of paths to that perfect draw is enormous.
Perhaps most moves (60+%) are losing because most moves drop a piece or pawn in
one move, but I don't think that makes them likely candidates for a WC player to
play.
Albert
>
>>Kasparov and many top players choose these extremely aggressive and double-edged
>>positions to try to obtain winning chances, not because they are incapable of
>>playing quieter and solider moves. They are trying very hard to find a way out
>>of the draw, which means taking risks, and that has been the entire tendency of
>>opening theory development. The lines that are dropped from GM play aren't
>>because they are deemed losing, but because they are not deemed to offer good
>>chances of not _drawing_.
>>
>>As to DBII, well, it was worse in many games despite its outstanding depth of
>>calculation, its win in game 6 is hard to understand, and the one in the second
>>game wasn't from the position. Kasparov psyched himself out, but wasn't beaten
>>at the board. Nunn analyzed one of the endgames and showed that Kasparov could
>>have won forcibly.
>
>Even at that, the machine played as well as he did. I guess we'll just have to
>build the perfect chess playing program and convince Kasparov to play it to find
>out. I'd hate to be accused of arguing about how many angels can dance on the
>head of a pin again.
>;-)
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