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Subject: Re: Computer Correspondence Chess Challenge (Ham)

Author: Dann Corbit

Date: 14:37:11 07/27/00

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On July 27, 2000 at 17:15:33, blass uri wrote:

>On July 27, 2000 at 16:31:51, Dann Corbit wrote:
>
>>Computers don't play like people at all.
>>
>>They formulate no plans, and have no goals except:
>>snack, snack, snack, snack ...
>>win (by accident!)
>>
>>Tactially, computers are better than any human on the planet.  Maybe an ELO of
>>3000 or higher.
>
>Computers are strong at short tactic but if the tactics is deep enough they can
>be outsearched.
>
>There are also some cases in endgames when part of them cannot see simple
>tactics because of null move prunning that is assuming that a move is not good
>if it has no threat(this can be a problem only in position of zunzwang and is
>not a problem in pawn endgames because programs do not use the null move
>prunning in this type of endgame)
>
>  Once you get out of the opening book, tactical blunders will be
>>incredibly rare.  Certainly GM's will make tactical blunders at ten times the
>>rate of a very strong computer program (just a guess -- it might be hundreds or
>>thousands of times higher).
>>
>>Strategically (positionally) computers are club players.  Some programmers have
>>added some board position knowlege, but they obviously don't play like GM's.
>
>I do not see how you decide about the positional level of them.
>They can often play very good positional moves(it may be because of search but
>it does not change the fact that club players will probably lose against
>computers even if they can aska computer if their move is a tactical
>blunder(more than 1/2 pawn error)
>
>The game of Steve Ham with black against nimzo is a good example because Steve
>Ham did not do a clear tactical error(there was no big change in the evaluation
>of nimzo) but Nimzo is probably going to win the game.
>
>It proves that even better than club players can have problems against computers
>even without tactical mistakes.
>>
>>Considering Deep Junior's play at Dortmund, I think open games at 40/2 are no
>>longer the exclusive property of GM's -- as Junior excelled.  Closed positions
>>did much better, but computer programmers can fight to achieve an open position.
>> Crafty [for example] has code especially for that purpose (to prevent rows of
>>locked pawns).
>
>I do not like it.
>I prefer to see computers play for closed positions if this is the right way to
>play.
>
>I am not sure if Crafty's code is going to help it against the best players
>because they may play for an open position if they see that the position give
>them an advantage.
>>
>>What the computer does, is search very deeply for the most expensive target it
>>can snack on without repercussion.  The strenght in this operation is
>>phenomenal, with a full 8 moves being possible at correspondence time controls
>>for many types of position.  At such types of calculations, the program will be
>>relatively flawless.
>>
>>What fools a computer, and why?
>>
>>A locked position fools a computer.  The reason is that it can take a long time
>>for something to happen.  This means you are *forced* to plan, which a computer
>>is unable to do.  If no big goal can be located in 8 full moves, it's play will
>>be completely aimless.
>
>I disagree because there are extensions and the computer can see the goal by the
>extensions.
>>
>>An overpowering massed force attack on the kingside sometimes fools computers.
>>That's because you may have to lose a lot of material to achieve the goal.  The
>>computer will see you throwing away pieces in your attack and decide "Surely he
>>won't do that..." by means of the alpha-beta search (and possibly by NULL move).
>> As long as the actual checkmate is too deep for the computer to see when the
>>attack is initiated, the computer won't see it.
>
>It depends on the program.
>chess system tal plays for king attack because it has big positional bonus and
>it can evaluate positions with material advantage as bad.
>
>
>>
>>Computers can be fooled by pawn races when the board is sparse (but not too
>>sparse!).  If you have paired pawns and a king or trouser pawns and a long way
>>to go, the opposing computer may not see it (the horizon effect).  I have seen
>>this effect at 40/2 games, but I don't know if a computer can be fooled by this
>>at correspondence time controls.  Once you are down to 6 or 7 chessmen, though,
>>the computer will play *flawlessly*.  This does not mean it will win!  If it is
>>in a losing position, it may still lose.  But if you slip and any win for the
>>opponent is possible it will definitely find it because of the endgame tablebase
>>files.
>
>It depends on the program part of the programs like chessmaster and tiger do not
>use tablebases.

Your post raises some very good issues, and also, I think you know better than
me because I have never played at correspondence rates against a computer since
a very long time!  (I used to play EdChess that way by letting the computer (a
286) think all night and then I would move in the morning.

I think some of the general principles do bear out at 40/2 (e.g. the GM's did
much better using closed positions than using open positions).

However, at correspondence time controls, I don't know if the ideas still work.
I *do* know that some strategies that do work at blitz do *not* work at 40/2.




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