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Subject: Re: Another blocked position -- Analysis with Crafty 17.10

Author: Ed Schröder

Date: 00:15:50 08/15/00

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On August 14, 2000 at 19:11:45, Olaf Jenkner wrote:

>On August 14, 2000 at 08:43:08, Enrique Irazoqui wrote:
>
>>This one is a MES position:
>>
>>[D]3B4/1r2p3/r2p1p2/bkp1P1p1/1p1P1PPp/p1P1K2P/PPB5/8 w - - 0 1
>>
>>After 6.f5, all programs I tried evaluate it from +11 to +17.
>>
>>Enrique
>>
>>[Event "?"]
>>[Site "?"]
>>[Date "????.??.??"]
>>[Round "?"]
>>[White "MES.941"]
>>[Black "?"]
>>[Result "*"]
>>[SetUp "1"]
>>[FEN "3B4/1r2p3/r2p1p2/bkp1P1p1/1p1P1PPp/p1P1K2P/PPB5/8 w - - 0 1"]
>>[PlyCount "11"]
>>
>>1. Ba4+ Kxa4 2. b3+ Kb5 3. c4+ Kc6 4. d5+ Kd7 5. e6+ Kxd8 6. f5 *
>
>The computer does not have to see the draw to solve this study.
>The solution can be found, when all other moves give a worse
>evaluation.
>To find the value of the drawn position I analysed the position
>after 1.Bxa4+ Kxa4 2.b3+ Kb5 3.c4+ Kc6 4.d5+ Kd7 5.e6+ Kxd8 :

There is another side effect you seem to forget. Black might for
instance Rc6 and I am pretty sure comps will capture the rook and
white will lose after all.

Ed





> 8     0.69 -13.51   1. Ke3 Kc7 2. fxg5 fxg5 3. Ke4 Ra8 4. Kf5 Rg8 5. Ke4
> 8->   0.70 -13.51   1. Ke3 Kc7 2. fxg5 fxg5 3. Ke4 Ra8 4. Kf5 Rg8 5. Ke4
> 9     1.84 -13.62   1. Ke3 Kc7 2. Ke4 Ra8 3. Kf5 Rg8 4. Ke4 Bb6 5. fxg5 <HT>
> 9->   2.01 -13.62   1. Ke3 Kc7 2. Ke4 Ra8 3. Kf5 Rg8 4. Ke4 Bb6 5. fxg5 <HT>
>10     4.58 -13.58   1. Ke3 Kc7 2. Ke4 Ra8 3. Kf5 Rg8 4. Ke4 Bb6 5. fxg5 fxg5 6.
>Kf5
>10->   4.61 -13.58   1. Ke3 Kc7 2. Ke4 Ra8 3. Kf5 Rg8 4. Ke4 Bb6 5. fxg5 fxg5 6.
>Kf5
>11    11.03 -13.62   1. Ke3 Kc7 2. Ke4 Ra8 3. Kf5 Rg8 4. Ke4 Bb6 5. fxg5 fxg5
>                     6. Kf5 Rg7
>11->  11.46 -13.62   1. Ke3 Kc7 2. Ke4 Ra8 3. Kf5 Rg8 4. Ke4 Bb6 5. fxg5 fxg5
>                     6. Kf5 Rg7
>12    26.06 -13.69   1. Ke3 Kc7 2. Ke4 Ra8 3. Kf5 Rg8 4. Ke4 Rbb8 5. Ke3 Rbf8
>                     6. f5 <HT>
>12->  26.32 -13.69   1. Ke3 Kc7 2. Ke4 Ra8 3. Kf5 Rg8 4. Ke4 Rbb8 5. Ke3 Rbf8
>                     6. f5 <HT>
>13     1:10 -14.01   1. Ke3 gxf4+ 2. Kxf4 Ra8 3. Ke4 Kc7 4. Kf3 Rg8 5. Kf2 Rbb8
>                     6. Ke1 f5 7. gxf5 Rbf8 8. Kd2 Rxf5
>13     1:17 -13.72   1. f5 Kc7 2. Ke3 Ra8 3. Ke4 Rg8 4. Kf3 Bb6 5. Ke4 Rf8
>                     6. Kf3 Rd8 7. Ke4
>13->   1:17 -13.72   1. f5 Kc7 2. Ke3 Ra8 3. Ke4 Rg8 4. Kf3 Bb6 5. Ke4 Rf8
>                     6. Kf3 Rd8 7. Ke4
>14     1:23 -13.72   1. f5 Kc7 2. Ke3 Ra8 3. Ke4 Rg8 4. Kf3 Bb6 5. Ke4 Rf8
>                     6. Kf3 Rd8 7. Ke4 Re8
>14->   1:23 -13.72   1. f5 Kc7 2. Ke3 Ra8 3. Ke4 Rg8 4. Kf3 Bb6 5. Ke4 Rf8
>                     6. Kf3 Rd8 7. Ke4 Re8
>15     1:36 -13.73   1. f5 Kc7 2. Ke3 Ra8 3. Ke4 Bb6 4. Kf3 Rbb8 5. Ke4 Rg8
>                     6. Ke3 Rgf8 7. Ke4 Rad8 8. Ke3
>15->   1:38 -13.73   1. f5 Kc7 2. Ke3 Ra8 3. Ke4 Bb6 4. Kf3 Rbb8 5. Ke4 Rg8
>                     6. Ke3 Rgf8 7. Ke4 Rad8 8. Ke3
>16     2:00 -13.75   1. f5 Kc7 2. Ke3 Ra8 3. Ke4 Bb6 4. Kf3 Rbb8 5. Ke4 Rg8
>                     6. Ke3 Rgf8 7. Ke4 Rad8 8. Ke3 Rfe8
>16->   2:06 -13.75   1. f5 Kc7 2. Ke3 Ra8 3. Ke4 Bb6 4. Kf3 Rbb8 5. Ke4 Rg8
>                     6. Ke3 Rgf8 7. Ke4 Rad8 8. Ke3 Rfe8
>
>It takes 13 plies to get a worse evaluation then -13.7 (which means draw).
>
>Now when the value of the draw is known, I analysed the position
>after 1.Bxa4+ Kxa4 2.b3+ Kb5 3.c4+ Kc6 4.d5+ Kd7 :
>
> 9     0.70  -9.26   1. exf6 exf6 2. Bxf6 gxf4 3. Bg5 Ra8 4. Bxf4 Rf8 5. Ke3 Bb6
> 9->   0.77  -9.26   1. exf6 exf6 2. Bxf6 gxf4 3. Bg5 Ra8 4. Bxf4 Rf8 5. Ke3 Bb6
>10     1.64  -9.07   1. exf6 exf6 2. Bxf6 gxf4 3. Bxh4 Ra8 4. Bf2 Rg8 5. Ke2 Rg5
>6. Kf3
>10->   1.77  -9.07   1. exf6 exf6 2. Bxf6 gxf4 3. Bxh4 Ra8 4. Bf2 Rg8 5. Ke2 Rg5
>6. Kf3
>11     4.65  -9.28   1. exf6 exf6 2. Bxf6 gxf4 3. Bg5 Ra8 4. Bxf4 Rf8 5. Ke3
>Re8+
>                     6. Kd3 Bb6 7. Bg5
>11->   4.85  -9.28   1. exf6 exf6 2. Bxf6 gxf4 3. Bg5 Ra8 4. Bxf4 Rf8 5. Ke3
>Re8+
>                     6. Kd3 Bb6 7. Bg5
>12    13.75  -9.23   1. exf6 exf6 2. Bxf6 gxf4 3. Bxh4 Ra8 4. Bg5 f3 5. Ke3 Rf8
>                     6. Kf2 Bd8 7. Bxd8 Kxd8
>12->  14.32  -9.23   1. exf6 exf6 2. Bxf6 gxf4 3. Bxh4 Ra8 4. Bg5 f3 5. Ke3 Rf8
>                     6. Kf2 Bd8 7. Bxd8 Kxd8
>13    22.93     --   1. exf6
>13    39.29 -10.11   1. exf6 Ke8 2. Bxe7 gxf4 3. Kd3 Rxe7 4. fxe7 Ra7 5. Ke2
>Rxe7+
>                     6. Kf2 Re3 7. g5 Rxb3 8. Kg2
>13->  41.82 -10.11   1. exf6 Ke8 2. Bxe7 gxf4 3. Kd3 Rxe7 4. fxe7 Ra7 5. Ke2
>Rxe7+
>                     6. Kf2 Re3 7. g5 Rxb3 8. Kg2
>14    43.65     --   1. exf6
>14     1:45 -10.88   1. exf6 Ke8 2. Bxe7 gxf4 3. g5 Rxe7 4. fxe7 Ra7 5. Ke2
>Rxe7+
>                     6. Kf2 Re3 7. g6 Rxh3 8. Ke1 Rxb3
>14->   2:03 -10.88   1. exf6 Ke8 2. Bxe7 gxf4 3. g5 Rxe7 4. fxe7 Ra7 5. Ke2
>Rxe7+
>                     6. Kf2 Re3 7. g6 Rxh3 8. Ke1 Rxb3
>15     2:05     --   1. exf6
>15     6:06 -11.37   1. exf6 Ke8 2. f7+ Kxf7 3. Bxa5 gxf4 4. Bd8 Kf6 5. Ke2 Ra8
>                     6. Kf3 Kg5 7. Bxe7+ Rxe7 8. Kf2 Re3 9. Kg2
>15->   7:18 -11.37   1. exf6 Ke8 2. f7+ Kxf7 3. Bxa5 gxf4 4. Bd8 Kf6 5. Ke2 Ra8
>                     6. Kf3 Kg5 7. Bxe7+ Rxe7 8. Kf2 Re3 9. Kg2
>16    19:14 -11.61   1. exf6 Ke8 2. f7+ Kxf7 3. Bxa5 gxf4 4. Bd8 Kf6 5. Ke2 Rd7
>                     6. Kf3 Kg5 7. Bc7 Rxc7 8. Ke4 Rb6 9. Kf3
>16->  20:11 -11.61   1. exf6 Ke8 2. f7+ Kxf7 3. Bxa5 gxf4 4. Bd8 Kf6 5. Ke2 Rd7
>                     6. Kf3 Kg5 7. Bc7 Rxc7 8. Ke4 Rb6 9. Kf3
>17    20:28     --   1. exf6
>17    89:06 -12.31   1. exf6 Ke8 2. f7+ Kxf7 3. Bxa5 Rxa5 4. f5 Kf6 5. Ke2 Ke5
>                     6. Ke1 Ra8 7. Kf1 Kd4 8. Ke2 <HT>
>17->  96:58 -12.31   1. exf6 Ke8 2. f7+ Kxf7 3. Bxa5 Rxa5 4. f5 Kf6 5. Ke2 Ke5
>                     6. Ke1 Ra8 7. Kf1 Kd4 8. Ke2 <HT>
>18    98:08     --   1. exf6
>18   277:16 -14.69   1. exf6 Ke8 2. Bxe7 gxf4 3. Ke2 Rxe7+ 4. fxe7 Ra7 5. Kf3
>Rxe7
>                     6. g5 Kf8 7. Kxf4 Re2 8. Kg4 Rxa2 9. Kxh4 Rb2 10. g6 Rxb3
>18   692:55     ++   1. Bxa5!!
>18   866:47 -12.82   1. Bxa5 dxe5 2. f5 Rxa5 3. Kd3 Kd6 4. Ke4 Rd7 5. Kd3 Raa7
>                     6. Ke2 Rac7 7. Ke3 Rb7 8. Kd3 Rb6 9. Ke3 Rd8
>18-> 872:25 -12.82   1. Bxa5 dxe5 2. f5 Rxa5 3. Kd3 Kd6 4. Ke4 Rd7 5. Kd3 Raa7
>                     6. Ke2 Rac7 7. Ke3 Rb7 8. Kd3 Rb6 9. Ke3 Rd8
>
>Crafty needs 18 plies to realize, that 1.exf5 is worse then 13.7 .
>Of course 1.Bxa5 loses also, but it is beyond the horizon.
>It's disappointing, that after 14 hours Crafty does not see the loss after Bxa5.
>
>To find the reason I analysed the position
>after 1.Bxa4+ Kxa4 2.b3+ Kb5 3.c4+ Kc6 4.d5+ Kd7 and now 5.Bxa5? dxe5 6.f5 Rxa5
>:
>
> 9     0.83 -12.68   1. Ke3 Rb8 2. Kf2 Rc8 3. Kf3 Rca8 <HT>
> 9->   0.84 -12.68   1. Ke3 Rb8 2. Kf2 Rc8 3. Kf3 Rca8 <HT>
>10     2.30 -12.78   1. Ke3 Rb8 2. Kf2 Kd6 3. Kf3 Ra6 4. Ke3 Raa8 5. Kf3 Rd8
>10->   2.31 -12.78   1. Ke3 Rb8 2. Kf2 Kd6 3. Kf3 Ra6 4. Ke3 Raa8 5. Kf3 Rd8
>11     5.18 -12.78   1. Ke3 Rb8 2. Kf2 Kd6 3. Kf3 Raa8 4. Ke3 Rd8 5. Ke4 Rac8 6.
>Ke3
>11->   5.18 -12.78   1. Ke3 Rb8 2. Kf2 Kd6 3. Kf3 Raa8 4. Ke3 Rd8 5. Ke4 Rac8 6.
>Ke3
>12    11.60 -12.78   1. Ke3 Rb8 2. Kf2 Kd6 3. Kf3 Raa8 4. Ke3 Re8 5. Kf3 Red8
>                     6. Ke3 Rac8
>12->  11.61 -12.78   1. Ke3 Rb8 2. Kf2 Kd6 3. Kf3 Raa8 4. Ke3 Re8 5. Kf3 Red8
>                     6. Ke3 Rac8
>13    31.55 -12.80   1. Ke3 Kd6 2. Kf2 Ra8 3. Kf3 Rd7 4. Ke4 Rf8 5. Kf3 Rf7
>                     6. Ke3 Rf8 <HT>
>13->  33.73 -12.80   1. Ke3 Kd6 2. Kf2 Ra8 3. Kf3 Rd7 4. Ke4 Rf8 5. Kf3 Rf7
>                     6. Ke3 Rf8 <HT>
>14     1:30 -12.80   1. Ke3 Kd6 2. Ke4 Ra8 3. Ke3 Rd7 4. Ke4 Rf8 5. Kf3 Rfd8
><HT>
>14->   1:30 -12.80   1. Ke3 Kd6 2. Ke4 Ra8 3. Ke3 Rd7 4. Ke4 Rf8 5. Kf3 Rfd8
><HT>
>15     3:49 -12.96   1. Ke3 Ra6 2. Kf3 e6 3. fxe6+ Rxe6 4. dxe6+ Kxe6 5. Kf2 Rd7
>                     6. Ke2 Rd4 7. Ke1 Rd3 8. Ke2 Rxh3 9. Kd2 Rxb3
>15->   3:51 -12.96   1. Ke3 Ra6 2. Kf3 e6 3. fxe6+ Rxe6 4. dxe6+ Kxe6 5. Kf2 Rd7
>                     6. Ke2 Rd4 7. Ke1 Rd3 8. Ke2 Rxh3 9. Kd2 Rxb3
>16     3:56     --   1. Ke3
>16    13:26 -15.87   1. Ke3 Ra6 2. Kf3 e4+ 3. Kxe4 e6 4. fxe6+ Rxe6+ 5. dxe6+
>Kxe6
>                     6. Kd3 Ke5 7. Kd2 Ke4 8. Kc2 Rd7 9. Kc1 <HT>
>16->  14:13 -15.87   1. Ke3 Ra6 2. Kf3 e4+ 3. Kxe4 e6 4. fxe6+ Rxe6+ 5. dxe6+
>Kxe6
>                     6. Kd3 Ke5 7. Kd2 Ke4 8. Kc2 Rd7 9. Kc1 <HT>
>17    14:52     --   1. Ke3
>
>It takes 16 (or 20) plies to get the value below 13.7 .
>
>Conclusion: The study is too hard for computers (I used a PII 333 MHz Hash
>48M/32M).
>            Perhaps it is possible to solve the position after 4 moves.
>
>Question: Does anybody have better results with other programs?
>          Maybe better knowledge about passed pawns can save some plies.



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