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Subject: Re: DB will never play with REBEL, they simple are afraid no to do well

Author: Ratko V Tomic

Date: 16:19:53 10/13/99

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>Look at programs that can [be set to] calculate only 2 plies.  Your 10 year old
>kids can beat it.  If we go to 5 plies, it is quite a good opponent.  At 10
>piles, they play brilliantly. At 18+ plies they would be "the gifted of the
>gifted of the gifted" as far as tactics are concerned, and I think such a
>machine would actually have strategic power from time to time (depending on the
>board condition).

Even the 18 plies in complex middle game (which may be 2-3 years off) still
hinge on the same old simple-minded evaluation of the terminal nodes. Unless you
find a clear cut advantage at that depth, the judgment of such position by a
strong human player is superior to material, square count and such simple
citeria. This depth eliminates only more of tactical shots (if there are many
left after certain depth but well before table-base level). So what the strength
gain is depends grat deal on the type of position. A human GM playing such
computer in a manner he would play another human would likely lose, since they
would generate typical kind of positions where the deeper search may find
something. But there arte positions where no tactical shots exist, or at least
no such that are beyond GM's vision. While these positions may be more rare,
when one plays in a normal manner (as if against another human), even the
relative bumbling patzers (like most of us) have gotten the programs into such
positions from time to time.

If there was a strong enough incentive & motivation (and maybe there will be
some day) for the chess professionals community to work out the openings and
strategies which would steer the game with great probability into such
positions, the current programs, DB and the rest, would drop down to 2000 level
or worse (depending on how complex such strategy may be for humans to carry
out). If I (a mere 2100 player over a decade ago) can get Fritz 5.32 etc to just
shuffle rooks on the back rank with no clue what to do next, with no systematic
plan or technique for getting there on my part, the real pros, with real
motivation, and few years to perfect it, could turn it into an almost certain
game flow. You don't need a table base to win most endgames which are winnable.
Yes there are odd/paradoxical positions here and there, but they could chip off
at best a tiny fraction of GM's points. You don't need the best move to win,
just a good enough move (chess programmers don't seem to know this, as yet).


>
>Look how hard they would make an expert work.  17% of the time, a new ply gives
>you a better move.  With 3 plies deeper, that is nearly 50% of the time you get
>a better move [(1-.83)^3] on average.  If you are not prepared for it, you will
>have to think really hard about why a particular choice was made.

I have seen few papers where they follow change of move choice with depth. But I
wouldn't say that a different move is automatically a "better move" as you
assume. The "better" here could mean one more square attacked by the program as
seen 12 plies deep (which often means nothing since fre moves later it can all
change). Even an apparent small material gain doesn't mean it is a better move.
If you look sometimes how a program goes queenside pawn hunting, seeing a
brilliant  10 ply combination to a win your b2 pawn, while you maybe see an
enemy Queen getting into his qeenside, likely to win a pawn or two, but counts
on his king side pawns to break open the program's castle and is readying his
pieces to take part in an attack 10-15 moves ahead. To draw programs queen into
such adventure, whenever chance occurs, I weaken my b2 or a2 pawns, knowing that
as soon as it sees a two-three move queen manouver to grab one or more of them
it won't be able to resist the temptation.






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