Author: Robert Hyatt
Date: 10:44:21 01/08/04
Go up one level in this thread
On January 08, 2004 at 13:30:23, Drexel,Michael wrote:
>On January 08, 2004 at 12:01:56, Robert Hyatt wrote:
>
>>On January 08, 2004 at 10:02:39, Anthony Cozzie wrote:
>>
>>>I've been trying to get some good test positions to rewrite my kingsafety with,
>>>and playing Gothmog will give you those :) Usually Zappa is slightly better than
>>>Gothmog. It is stronger tactically (gets more nps and does not do all dubious
>>>forward pruning) and its mobility is good enough that it plays reasonable moves
>>>most of the time. Usually Zappa will get its wins in the endgame, but Gothmog
>>>will get in enough king attacks that the score is close. During one of the test
>>>games, this position came up (Zappa-white, Gothmog-black):
>>>
>>>[D]r2qk2r/pb4pp/3bn3/1P1ppp2/8/BQP5/P2NBPPP/R4RK1 b kq - 4 17
>>>
>>>Where Gothmog evaluated itself as +1, and Zappa thought it was about equal -
>>>which is of course ludicrous since black has a big advantage. I was less than
>>>happy with Zappa being blown off the board in 20 moves and not even realizing
>>>it, so I wrote some code to evaluate control of the board. But I made a mistake
>>>and tuned it way too high.
>>>
>>>What was amazing was the result. Every game went like this:
>>>
>>>Zappa pushes pawns
>>>Gothmog sacrifices a piece for the pawns
>>>Gothmog thinks its down .5
>>>Zappa thinks its up 2
>>>Zappa wins back pawns and the game with its extra piece/exchange
>>>
>>>Result: Zappa scores 86% - +18-0=7.
>>>
>>>Moral of the story: If you want to beat Gothmog, triple your space evaluation.
>>>
>>>anthony
>>>
>>>caveat: This was done under Arena, with the arena books, which need a bit of
>>>work.
>>
>>Another moral: Don't trade a piece for 2-3 pawns. It will come back to
>>haunt you more than it doesn't.
>
>It depends. In the late endgame it is usually advisable to trade a piece for 3
>pawns.
>
>[D] 8/7R/6p1/4Kpk1/p1B5/8/8/4r3 w - - 0 63
>
>Crafty was happy with this hopeless position and got a lesson in the game:
>
>Crafty 19.06 - Hiarcs 9
>8/7R/6p1/4Kpk1/p1B5/8/8/4r3 w - - 0 1
>
>Analysis by Crafty 19.06:
>
>63.Kd6 f4 64.Bd5 a3 65.Rg7 Kf5 66.Rf7+ Kg4 67.Rg7
> = (-0.22) Depth: 8 00:00:00 109kN
>63.Kd4 f4 64.Bd3 a3 65.Ra7 Ra1 66.Ra5+ Kg4 67.Bxg6
> = (0.00) Depth: 8 00:00:00 177kN
>63.Kd4 f4 64.Bd3 a3 65.Ra7 Ra1 66.Ra5+ Kg4 67.Bxg6
> = (0.00) Depth: 8 00:00:00 178kN
>63.Kd4 f4 64.Bd5 a3 65.Rh3 Re3 66.Rxe3 fxe3 67.Kxe3 Kf5
> = (-0.01) Depth: 9 00:00:00 312kN
>63.Kd4 f4 64.Bd5 a3 65.Rh3 Re3 66.Rxe3 fxe3 67.Kxe3 Kf5
> = (-0.01) Depth: 9 00:00:00 379kN
>63.Kd4 f4 64.Rg7 f3 65.Rf7 Kg4 66.Bd5 Rf1 67.Be4 g5
> = (-0.06) Depth: 10 00:00:01 1025kN
>63.Kd4 f4 64.Rg7 f3 65.Rf7 Kg4 66.Bd5 Rf1 67.Be4 g5
> = (-0.06) Depth: 10 00:00:02 1181kN
>63.Kd4 f4 64.Rg7 f3 65.Bd3 Re6 66.Rf7 Rf6 67.Rxf6 Kxf6 68.Ke3 a3 69.Kxf3
> = (-0.11) Depth: 11 00:00:04 2652kN
>63.Kd4 f4 64.Rg7 f3 65.Bd3 Re6 66.Rf7 Rf6 67.Rxf6 Kxf6 68.Ke3 a3 69.Kxf3
> = (-0.11) Depth: 11 00:00:05 3132kN
>63.Kd4 f4 64.Bd5 Kg4 65.Be4 a3 66.Rh2 g5 67.Rg2+ Kh4 68.Rh2+ Kg3 69.Rg2+ Kh4
> = (0.00) Depth: 12 00:00:17 9699kN
>63.Kd4 f4 64.Bd5 Kg4 65.Be4 a3 66.Rh2 g5 67.Rg2+ Kh4 68.Rh2+ Kg3 69.Rg2+ Kh4
> = (0.00) Depth: 12 00:00:18 10240kN
>63.Kd4 f4 64.Bd5 Kg4 65.Ra7 g5 66.Be4 Rd1+ 67.Ke5 f3 68.Rf7 Rf1 69.Ra7 Kg3
>70.Rxa4
> = (-0.20) Depth: 13 00:00:31 17255kN
>63.Kd4 f4 64.Bd5 Kg4 65.Ra7 g5 66.Be4 Rd1+ 67.Ke5 f3 68.Rf7 Rf1 69.Ra7 Kg3
>70.Rxa4
> = (-0.20) Depth: 13 00:00:42 23499kN
>63.Kd4 f4 64.Bd5 Kg4 65.Ra7 g5 66.Bc6 Rc1 67.Bd5 f3 68.Rf7 Rd1+ 69.Ke4 Rf1
>70.Ke5
> = (-0.14) Depth: 14 00:01:28 48402kN
>
>[Event ""]
>[Site ""]
>[Date "2003.11.27"]
>[Round "1"]
>[White "Crafty 19.06"]
>[Black "Hiarcs 9"]
>[Result "0-1"]
>[ECO "B92"]
>[Annotator "0.56;0.65"]
>[SetUp "1"]
>[FEN "8/7R/6p1/4Kpk1/p1B5/8/8/r7 b - - 0 62"]
>[PlyCount "43"]
>[TimeControl "300+3"]
>
>62... Re1+ {(f4) -1.59/12 5} 63. Kd4 {-0.15/12 5} f4 {-1.51/11 6} 64. Bd5 {
>-0.20/11 6} Kg4 {-1.53/11 4} 65. Rh6 {(Rh2) -0.36/11 5} g5 {(Kf5) -1.84/10 3}
>66. Be6+ {(Rh2) -0.19/11 5} Kf3 {-1.84/11 6} 67. Rh3+ {(Bd5+) -0.19/11 7} Kf2 {
>-1.92/11 5} 68. Bf5 {-0.36/11 5} Rg1 {-1.84/10 5} 69. Ke4 {-0.35/11 11} Rg3 {
>-1.84/11 4} 70. Rh2+ {-0.70/11 5} Kg1 {-1.84/11 4} 71. Ra2 {-0.31/12 5} f3 {
>(Re3+) -1.97/11 4} 72. Ra1+ {-1.42/11 5} Kg2 {-2.13/12 4} 73. Bd7 {
>(Ke3) -1.52/12 5} f2 {-2.51/11 4} 74. Bb5 {-1.48/12 5} Rf3 {-2.38/11 5} 75.
>Bf1+ {-1.64/12 4} Kg3 {-2.59/12 4} 76. Be2 {-1.72/12 4} Rf4+ {(Rf8) -2.75/11 3}
>77. Ke3 {(Kd3) -2.11/12 4} g4 {-2.85/11 4} 78. Bf1 {-2.35/12 5} Rf3+ {
>-3.43/11 4} 79. Ke2 {-2.91/12 5} a3 {-3.63/12 4} 80. Rd1 {(Kd2) -3.40/12 4} Rb3
>{-5.44/11 3} 81. Ra1 {-7.73/12 5} Rb2+ {-10.40/11 3} 82. Ke3 {(Kd3) -10.95/13 4
>} a2 {-11.05/11 4} 83. Ke4 {-12.54/13 7} Rb1 {-12.86/12 4} 0-1
>
>Michael
I don't say it never happens. But I will say that 95%+ of the time,
trading a piece for 3 pawns loses. In that game, crafty would trade if
it could, as it knows that the side with the pawns is the only side that
can win. Either it couldn't find a way to trade, or it has a bug, because
it does have specific knowledge for the case where the last 3 pawns come off
the board.
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