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Subject: Re: Question remains: how do you defend against 43.Rc6

Author: Wayne Lowrance

Date: 06:44:46 10/20/00

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On October 19, 2000 at 23:08:13, Robert Hyatt wrote:

>On October 19, 2000 at 22:19:03, Christophe Theron wrote:
>
>>On October 19, 2000 at 18:11:40, Robert Hyatt wrote:
>>
>>>On October 19, 2000 at 15:29:11, Christophe Theron wrote:
>>>
>>>>On October 19, 2000 at 14:43:34, Robert Hyatt wrote:
>>>>
>>>>>On October 19, 2000 at 12:13:07, Christophe Theron wrote:
>>>>>
>>>>>>On October 19, 2000 at 10:56:58, Uri Blass wrote:
>>>>>>
>>>>>>>On October 19, 2000 at 10:17:32, Thorsten Czub wrote:
>>>>>>>
>>>>>>>>[Event "Open Dutch CC 2000"]
>>>>>>>>[Site "Leiden NED"]
>>>>>>>>[Date "2000.10.14"]
>>>>>>>>[Round "02"]
>>>>>>>>[White "Tiger"]
>>>>>>>>[Black "Nimzo 8"]
>>>>>>>>[Result "1-0"]
>>>>>>>>[ECO "D20"]
>>>>>>>>
>>>>>>>>1.d4 d5 2.c4 dxc4 3.e4 Nf6 4.e5 Nd5 5.Bxc4 Nb6 6.Bb3 Nc6 7.Ne2 Bf5
>>>>>>>>8.Nbc3 e6 9.a3 Qd7 10.O-O Be7 11.Be3 O-O-O 12.Rc1 f6 13.exf6 gxf6
>>>>>>>>14.Na4 Nd5 15.Bc4 Na5 16.Ba2 Bg4 17.Nac3 Nxc3 18.Rxc3 Kb8 19.f3 Bh5
>>>>>>>>20.b4 Nc6 21.b5 Na5 22.Qa4 b6 23.Nf4 Bf7 24.Rfc1 Bd6 25.Nd3 Rhg8
>>>>>>>>26.Nc5 Bxc5 27.dxc5 e5 28.Bxf7 Qxf7 29.cxb6 cxb6 30.Qc2 Qg6 31.Qa2 f5
>>>>>>>>32.Kh1 f4 33.Bg1 h5 34.Qe2 Qf6 35.a4 h4 36.h3 Qg5 37.R1c2 Rd7
>>>>>>>>38.Qe1 Rdg7 39.Qe4 Rd7 40.Qe2 Rgd8 41.Qe1 Qe7 42.Qe4 Qg5 43.Rc6 Nxc6
>>>>>>>>44.bxc6 Rc7 45.a5 bxa5 46.Qe2 a4 47.Qb5+ Ka8 48.Qxa4 Qf6 49.Qa5 Qe7
>>>>>>>>50.Re2 Rdc8 51.Rxe5 Qg7 52.Qe1 a6 53.Qe2 Rxc6 54.Re7 Qc3 55.Kh2 Qb4
>>>>>>>>56.Ra7+ Kb8 57.Qe5+ R8c7 58.Qh8+ Rc8 59.Qxh4 Rc1 60.Bf2 R1c6
>>>>>>>>61.Qg5 R8c7 62.Qg8+ Rc8 63.Qg7 R8c7 64.Qh8+ Rc8 65.Qe5+ R8c7 66.h4 Rc2
>>>>>>>>67.Bd4 R2c4 68.Qe8+ Rc8 69.Qe4 R8c6 70.Rd7 a5 71.Be5+ Ka8 72.Rd8+ Ka7
>>>>>>>>73.Qh7+ Ka6 74.Rb8 Rb6 75.Ra8+ Kb5 76.Qd7+ Rcc6 77.Bc7 Qe1 78.Re8 Qxh4+
>>>>>>>>79.Kg1 Qf6 80.Re5+ Kc4 81.Bxb6 Qxe5 82.Qxc6+ Kb3 83.Qe4 Qa1+
>>>>>>>>84.Kf2 Qb2+ 85.Qe2 Qxe2+ 86.Kxe2 a4 87.Kd2 a3 88.Ba5 a2 1-0
>>>>>>>>
>>>>>>>>please mention different defenses for BLACK, i will ask Gambit-Tiger
>>>>>>>>what he would have played for WHITE then.
>>>>>>>>
>>>>>>>>Gambit-Tiger 1.0 played 43.Rc6 with +2.28 in iteration 12.
>>>>>>>>The move was found from the beginning of computation (+2.02)
>>>>>>>>and it exects black to play Rf7 instead of 43...Nxc6.
>>>>>>>>
>>>>>>>>thanks in forward.
>>>>>>>
>>>>>>>Amir Ban also replied it.
>>>>>>>
>>>>>>>See http://www.icdchess.com/forums/1/message.shtml?133317
>>>>>>>
>>>>>>>Amir believes that the sacrifice gives chances for both sides to win.
>>>>>>>I am interested to know if tiger can get more than 50% against other programs by
>>>>>>>Rc6.
>>>>>>>
>>>>>>>My guess is that the result of Rc6(assuming no mistakes) is a draw and the
>>>>>>>question is if tiger is smart enough to get practically more than 50% with Rc6.
>>>>>>>
>>>>>>>The only way to know is by testing gambittiger against other programs from the
>>>>>>>position after Rc6.
>>>>>>>
>>>>>>>Uri
>>>>>>
>>>>>>
>>>>>>
>>>>>>Yes, I would be very interested in these test games from the Rc6 position.
>>>>>>
>>>>>>It would tell us more than the "Uhh, it's risky I don't want Crafty to play
>>>>>>this" discussion we have already seen.
>>>>>>
>>>>>>
>>>>>>
>>>>>>    Christophe
>>>>>
>>>>>
>>>>>maybe it would, maybe it wouldn't.\
>>>>>
>>>>>if you know what I mean...
>>>>
>>>>
>>>>
>>>>I guess we know what you mean. You'll stick with a shy evaluation and a shy
>>>>QSearch.
>>>>
>>>>
>>>>
>>>>    Christophe
>>>
>>>
>>>Nope.  Guess it was too vague an implication.
>>>
>>>More simple:  Just because a program beats another program after playng move
>>>X, does _not_ mean move X is correct.  It could mean any of the following:
>>>
>>>1.  move X is correct and wins, period.
>>>
>>>2.  move X is wrong and the opponent simply wasn't good enough or fast
>>>enough to find the refutation.
>>>
>>>If you are happy in case 2, fine.
>>
>>
>>
>>Yes, I'm very happy with #2. I would like to see much more of #2 in the game my
>>program plays.
>>
>>
>>
>>
>>>  If that is the case this move Rc6
>>>belongs in (and it seems that it is).  I am not happy with 2, myself.
>>>Because some program will be fast enough or good enough and find the
>>>right moves.  I want to play moves because they are good, or because they
>>>win no matter what my opponent does.  I don't want to play them just because
>>>he didn't see the refutation _this_ time.  Using _this_ hardware.
>>
>>
>>
>>Computers and human players do #2 ALL THE TIME.
>>
>>Every move played by a computer or a human player is a #2. Because we all use an
>>heuristic evaluation function (and programs use it on top of a limited depth
>>alpha-beta search).
>
>I disagree.  In _many_ cases, humans make moves because they _know_ the move
>is the right move.  By deep calculation _and_ past experience.

Bob, I don't think I can agree with this. There _are_ moves that are obviously
correct but do not need deep thinking, they just _are_ correct. I do not think
he is talking about those moves. There are positions that after best calculation
can be refuted and therefore were bad, _there are no perfect chess games_,.
Christophe is satisfied with a win that is brought about by the opponent not
finding the correct play. That describes I guess all chess matches.

I think you are chasing a goal with Crafty that is hurting the development of
your program. I believe you are _one_ of the elite chess programmars, believe me
I read every one of your comments as well as your peers.

Wayne
>
>
>>
>>You are assuming that keeping the material balance is the way to go (that's why
>>you don't like the case #2), and you are using this assumption to convince
>>yourself that it is right!
>>
>>While the computers are not able to compute deep enough to see the real outcome
>>of the game, we have to live with heuristic evaluation functions.
>>
>>Talking about the "right" moves does not help. When a human or a computer plays
>>a move, he does not know for sure it is the "right" move.
>>
>>So I have no problem to win by playing a move that is not the "right" one,
>>because you do the same all the time!
>>
>>And if I win by playing a move that is not correct, you can call me stupid. But
>>don't forget to say that my opponent has been even more stupid.
>>
>>
>
>
>
>The problem is your opponent can get 'smarter'.  And as he gets smarter,
>you look more and more stupid.  This is why I try to watch so many games on
>ICC.  Several dozen of us watched a couple of GMs go at Scrappy (Crafty that
>only plays humans on ICC) last evening.  It won almost every game, only giving
>up a couple of draws out of 40+ games.  But in watching, _I_ saw some things
>that were not right.  And even though the opponent lost the game, I saw places
>where he could have played much better moves.  And he might well have won as a
>result.
>
>
>IE if my program plays Rc6 and I can prove it is correct, I am happy.  If I
>can prove it is bad, even though it won the game, I am not happy.  If I can't
>prove it either way, I am concerned.  That was the point here.  I want my fate
>in my hands, not resting on whether my opponent overlooks something or not.
>
>Yes games are often won/lost due to oversights.  But in an even position, if
>my opponent misses something, I might win.  If he doesn't, I won't necessarily
>lose.  If I toss a piece, and he overlooks something it works.  If he doesn't,
>I lose.  I don't particularly relish that case.
>
>
>>
>>    Christophe



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