Author: Chuck
Date: 18:26:42 08/27/05
Go up one level in this thread
On August 24, 2005 at 12:36:48, Robert Hyatt wrote:
>On August 24, 2005 at 11:59:58, Uri Blass wrote:
>
>>On August 24, 2005 at 11:14:48, Robert Hyatt wrote:
>>
>>>On August 24, 2005 at 03:05:25, Uri Blass wrote:
>>>
>>>>On August 24, 2005 at 01:23:26, Majd Al-Ansari wrote:
>>>>
>>>>>A human will immediately assess that black has a passed pawn on kingside so his
>>>>>own passed pawn on queenside cannot be supported by the king .... therefore an
>>>>>obvious draw without any calculation needed.
>>>>
>>>>I think that you overestimate humans.
>>>>I was not talking about the top humans but about the big majority of humans who
>>>>play in tournaments.
>>>>
>>>>Of course humans can see that black cannot support the passed pawns by the king
>>>>after some thinking but not immediately.
>>>
>>>Sorry, but I disagree here. But then I have worked on this exact code in Crafty
>>>many times. I don't even have to think about the king-side majority that
>>>becomes a passed pawn. So when I saw the position, my only question was "can
>>>black do anything on the queenside without the king, because the king has to
>>>restrain white's passed pawn on the kingside.
>>>
>>>After looking for a few seconds, I thought "no". So now it does become some
>>>calculation to see if either can win when both have passers on opposite wings.
>>>Since white's king is positioned OK, didn't take me much to come up with
>>>"draw"...
>>
>>I know that basically 2 pawns cannot win without the king but I also know
>>basically that with 2 pawn advantage in pawn endgame you can win and when you
>>have 2 passed pawns and the oponnent only has pawn majority it seems to me
>>thatit probably a win for the side with 2 passed pawns.
>>
>>Only after thinking about it I see that the king cannot support the pawns.
>>
>>pawn majority of 2 against 1 is not something that I am afraid of based on
>>experience and here is an example
>>
>>[D]8/8/pk4pp/8/PP5K/8/8/8 w - - 0 1
>>
>>pawn majority does not help white and note that black has only one pawn
>>advantage and not 2 pawn advantage.
>>
>>Uri
>
>that isn't a pawn majority in my calculations. The pawn can't advance to make a
>passed pawn, it is just a pawn liquidation that loses a pawn.
>
>Also, two connected passers against a single passer loses. The king can't stop
>two connected passers. The only calculation I have to do here is to answer the
>question "can one side produce two connected passers against the other side's
>single passer?" If so, the two connected passers have to be stopped, losing the
>single passer and the game...
>
>I actually have code in Crafty to handle this specific case (a protected passer
>wins against an isolated passer if the king can catch the isolated passer)...
Just to find out what the best can see, I ran this all night on Shredder 9.
Here's the analysis (in short, Shredder 9.1 still sees a win for Black but
doesn't play the captures):
[d]8/2p2kp1/1p2p3/2p1p1PP/2P1P3/1r2BK2/4R3/3n4 b - -
Engine: Shredder 9 UCI (64 MB)
by Stefan Meyer-Kahlen
11/25 0:01 +3.19 1...c6 2.Re1 Rd3 3.Ke2 (165.299) 118
11/25 0:01 +3.20++ 1...Rc3 (209.115) 142
11/25 0:01 +3.22 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.h6 Kg8
5.Ra3 gxh6 6.gxh6 Kh7 7.Ra7 (218.434) 145
12/21 0:01 +3.31 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.h6 Kg8
5.Rb3 Rd4 6.Ke3 Rd1 7.hxg7 Kxg7 (314.712) 184
13/26 0:02 +3.47 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.Re1 Rc3+
5.Kg4 b5 6.h6 Kg8 7.Rd1 Re3 8.hxg7 Kxg7 (541.686) 253
14/28 0:02 +3.56 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.Ra3 Rd4
5.Ra7 Rd7 6.h6 Kg6 (975.860) 330
15/38 0:04 +3.46 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxe3+ (1.789.773) 437
16/31 0:05 +3.46 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxe3+
4.Kxe3 (2.702.723) 492
17/38 0:07 +3.46 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxe3+
4.Kxe3 (3.998.171) 524
18/42 0:15 +3.45 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxe3+
4.Kxe3 (9.202.846) 596
18/42 0:21 +3.46++ 1...Rd3 (12.672.241) 590 TB:3
18/42 0:21 +3.46 1...Rd3 2.Re1 Nxe3 (12.856.806) 589 TB:3
19/44 0:38 +3.42 1...Rd3 2.Re1 Kg8 3.Ke2 Rxe3+ 4.Kxd1 Rc3
5.g6 (26.619.111) 691 TB:3
19/44 0:54 +3.43++ 1...b5 (36.128.545) 657 TB:35
19/48 1:01 +3.43 1...b5 2.Re1 (39.764.864) 645 TB:64
20/50 1:18 +3.25 1...b5 2.Re1 Nxe3 3.Rxe3 Rxe3+
4.Kxe3 b4 5.Kd3 Ke7 6.Kc2 Kf8 7.Kb2 Kf7
8.Kb3 Ke8 9.Kc2 (47.131.157) 600 TB:144
20/50 1:22 +3.26++ 1...Rd3 (49.036.371) 594 TB:147
20/50 1:34 +3.42 1...Rd3 2.Re1 Kg8 3.Ke2 Rxe3+ 4.Kxd1 Rc3
5.g6 Rxc4 6.Rf1 Rd4+ 7.Kc2 Rxe4 (56.599.039) 598 TB:147
21/48 2:14 +3.39 1...Rd3 2.Re1 Kg8 3.Ke2 Rxe3+ 4.Kxd1 Rh3
5.h6 gxh6 6.gxh6 Kf7 7.Kd2 Rxh6
8.Rg1 Ke7 9.Rg8 Kd6 10.Rd8+ Kc6 (78.804.151) 586 TB:187
21/48 2:34 +3.40++ 1...Rc3 (90.368.175) 584 TB:278
21/48 3:16 +3.65 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.Ra3 Rd4
5.Ra1 Rd8 6.Ke3 c4 7.h6 (110.199.757) 561 TB:399
22/47 4:03 +3.67 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.Ra3 Rd4
5.Ra1 Rd8 6.Ke2 c4 7.Rf1+ (132.600.797) 544 TB:682
23/48 6:20 +3.69 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.Re1 Rd4
5.Rh1 Rd3+ 6.Ke2 c4 7.h6 gxh6 8.gxh6 Kg8
9.Rh5 Kh7 10.Rxe5 Rd6 (196.041.654) 515
TB:2.034
24/49 9:31 +3.72 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.Ra3 Rd4
5.Ra7 Rd7 6.Kg4 c4 7.Ra8 Ke7 (286.751.234) 502
TB:4.391
25/56 16:47 +3.50 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.Ra3 Rd4
5.Ra7 Rd7 6.Ra4 Rd8 7.Ra7 (532.880.516) 528
TB:10.900
26/57 30:18 +3.75++ 1...Rc3 2.Re1 (933.762.404) 513
TB:36.033
26/57 31:10 +3.75 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.Ra3 Rd4
5.Ra7 Rd7 6.Ra4 Ke7 7.Ra1 b5 8.Ra5 (957.971.410) 512
TB:36.854
27/60 40:20 +3.50-- 1...Rc3 2.Re1 (1.242.014.625) 513
TB:53.061
27/60 56:10 +3.12 1...Rc3 2.Re1 Nxe3 3.Rxe3 Rxc4 4.g6+ Ke7
5.Re1 Rd4 6.Kg4 b5 7.h6 gxh6 8.Kh5 Kf8
9.Kxh6 Kg8 (1.920.157.540) 569
TB:74.260
27/60 60:18 +3.13++ 1...Rd3 (2.036.798.326) 562
TB:80.728
27/62 72:18 +3.47 1...Rd3 2.Re1 Kg8 3.Ke2 Rxe3+ 4.Kxd1 Rh3
5.h6 gxh6 6.gxh6 Kf7 7.Kc2 Rxh6
8.Rg1 Ke7 (2.465.708.334) 568
TB:102.150
28/59 108:33 +3.62 1...Rd3 2.Re1 Kg8 3.Ke2 Rxe3+ 4.Kxd1 Rh3
5.g6 Rxh5 6.Ke2 Rg5 7.Rd1 (3.355.979.633) 515
TB:225.682
29/60 156:53 +3.63 1...Rd3 2.Re1 Kg8 3.Ke2 Rxe3+ 4.Kxd1 Rh3
5.g6 Rxh5 6.Ke2 Rg5 7.Rd1 Rxg6 8.Rd7 Kf8
9.Rxc7 Rg2+ 10.Kd3 Rg3+ (4.499.167.940) 477
TB:387.450
30/62 273:38 +3.80 1...Rd3 2.Re1 Kg8 3.Ke2 Rxe3+ 4.Kxd1 Rh3
5.h6 Rc3 6.Rh1 gxh6 7.gxh6 (6.899.900.505) 420
TB:1.054.328
31/67 468:37 +3.82 1...Rd3 2.Re1 Kg8 3.Ke2 Rxe3+ 4.Kxd1 Rh3
5.g6 Rxh5 6.Ke2 Rg5 7.Rd1 Rxg6 8.Rd7 Kf8
9.Rxc7 Rg2+ 10.Kd3 Rg3+ (10.657.745.565) 379
TB:2.293.137
best move: Rb3-d3 time: 810:07.282 min n/s: 353.759 CPU 69.7% n/s(1CPU):
507.545 nodes: 17.195.256.591 TB: 4.310.789
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