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Subject: Re: To NON-believers in EGTB benefits... (a better example)

Author: Uri Blass

Date: 00:25:07 11/21/05

Go up one level in this thread

On November 21, 2005 at 02:38:09, Mike Hood wrote:

>The following position is a better example of the usefulness of endgame
>tablebases. The only winning move for White is Rg6. I allowed Fruit 2.1 (without
>tablebases) 10 minutes for a search.

This example show the negative value of EGTB

How much time does your program need to find Kxb3 that is the only practical
chance to save the game

[D]8/8/R7/8/1k6/1B1P4/6b1/K7 b - - 0 1

Fruit2.2.1 with all the 4 piece tablebases and 3 vs 2 tablebases cannot find it
in few minutes

New game,
8/8/R7/8/1k6/1B1P4/6b1/K7 b - - 0 1

Analysis by Fruit 2.2.1:

1...Kxb3
  +-  (2.51)   Depth: 1/3   00:00:00
1...Kxb3
  +-  (#73)   Depth: 2/5   00:00:00
1...Bf3 2.Kb2
  +-  (5.85)   Depth: 2/5   00:00:00
1...Kb5 2.Bc4+ Kc5
  +-  (5.68)   Depth: 2/5   00:00:00
1...Kc3 2.Rg6
  +-  (5.62)   Depth: 2/5   00:00:00
1...Kc3 2.Rg6 Kxb3 3.Rxg2
  +-  (5.64)   Depth: 3/6   00:00:00
1...Kc3 2.Bd5 Bh3 3.Rh6
  +-  (6.01)   Depth: 4/9   00:00:00
1...Kb5 2.Bc4+ Kc5 3.Kb2 Bf3
  +-  (5.96)   Depth: 4/9   00:00:00
1...Bf3 2.Kb2 Kc5 3.Ra5+ Kd4
  +-  (5.95)   Depth: 4/9   00:00:00
1...Kc5 2.Bd5 Bh3 3.Ra5+ Kd4
  +-  (5.91)   Depth: 4/9   00:00:00
1...Bf1 2.Bc4 Kc3 3.Ra3+ Kd4
  +-  (5.78)   Depth: 4/9   00:00:00
1...Bf1 2.Bc4 Kc3 3.Ra3+ Kd4 4.Kb2
  +-  (5.98)   Depth: 5/11   00:00:00
1...Kc5 2.Kb2 Kd4 3.Rg6 Bf3
  +-  (5.95)   Depth: 5/11   00:00:00
1...Kc5 2.Kb2 Kd4 3.Rd6+ Kc5 4.Rf6 Bc6 5.Rf5+ Kd4
  +-  (5.96)   Depth: 6/13   00:00:00  13kN
1...Bf1 2.Bc4 Kc3 3.Ra3+ Kd4 4.Kb2 Bg2
  +-  (5.93)   Depth: 6/13   00:00:00  16kN
1...Kc3 2.Bd5 Bf1 3.Be4 Be2 4.Rc6+ Kd4
  +-  (5.81)   Depth: 6/13   00:00:00  20kN
1...Kc3 2.Bd5 Bf1 3.Ra3+ Kd4 4.Be4 Be2 5.Kb2
  +-  (5.93)   Depth: 7/13   00:00:00  26kN, tb=6
1...Bf1 2.Bc4 Kc3 3.Ra3+ Kd4 4.Kb2 Be2 5.Kc2
  +-  (5.86)   Depth: 7/15   00:00:00  32kN, tb=6
1...Bf1 2.Bc4 Kc3 3.Ra3+ Kd4 4.Kb2 Be2 5.Kc2 Bf3
  +-  (5.84)   Depth: 8/16   00:00:00  48kN, tb=6
1...Bf1 2.Bc2 Kc3 3.Rc6+ Kd2 4.Kb2 Bg2 5.Rb6 Ke3 6.Kc3
  +-  (5.88)   Depth: 9/16   00:00:00  77kN, tb=6
1...Bf1 2.Bc2 Kc3 3.Rc6+ Kd4 4.Rc4+ Ke3 5.Re4+ Kd2 6.Kb2 Bg2 7.Re5 Bf3
  +-  (5.95)   Depth: 10/19   00:00:00  139kN, tb=6
1...Bf1 2.Kb2 Be2 3.Ra4+ Kc5 4.Kc3 Bf3 5.d4+ Kd6 6.Ra6+ Kc7 7.d5 Be4 8.Kd4
  +-  (6.49)   Depth: 11/23   00:00:00  525kN, tb=7
1...Kc3 2.Bd5 Bh3 3.Be4 Bd7 4.Ra3+ Kd4 5.Ra5 Bc8 6.Ra4+ Ke3 7.Kb2 Be6
  +-  (6.04)   Depth: 11/23   00:00:00  625kN, tb=7
1...Kc3 2.Bd5 Bh3 3.Be4 Bd7 4.Kb1 Bg4 5.Rc6+ Kd4 6.Rg6 Bh5 7.Rg7 Be2
  +-  (6.17)   Depth: 12/23   00:00:00  736kN, tb=30
1...Kc3 2.Bd5 Bh3 3.Be4 Bd7 4.Kb1 Bg4 5.Rc6+ Kd4 6.Rg6 Bh5 7.Rd6+ Ke3 8.Rf6 Bg4
  +-  (6.14)   Depth: 13/23   00:00:01  983kN, tb=38
1...Kc3 2.Bd5 Bh3 3.Be4 Bd7 4.Kb1 Bg4 5.Ra3+ Kd4 6.Kc2 Be6 7.Ra4+ Ke3 8.Ra6 Bf7
9.Kc3
  +-  (6.24)   Depth: 14/23   00:00:01  1316kN, tb=49
1...Kc3 2.Bd5 Bh3 3.Be4 Bd7 4.Kb1 Bg4 5.Ra3+ Kd4 6.Kc2 Be6 7.Ra4+ Ke3 8.Ra6 Bc4
9.dxc4 Kxe4
  +-  (6.27)   Depth: 15/25   00:00:01  1902kN, tb=74
1...Kc3 2.Ra3 Kd4 3.Ra4+ Kc5 4.d4+ Kb6 5.d5 Bh3 6.Kb2 Kc5 7.Ra6 Kb5 8.Rf6 Kc5
9.d6 Bd7 10.Kc3
  +-  (6.61)   Depth: 16/31   00:00:07  8414kN, tb=607
1...Kc3 2.Ra3 Kd4 3.Ra4+ Kc5 4.d4+ Kb6 5.d5 Bh3 6.Kb2 Kc5 7.Ra6 Bd7 8.Kc3 Bb5
9.Rf6 Bd7 10.d6 Bc6
  +-  (6.74)   Depth: 17/31   00:00:09  11322kN, tb=929
1...Kc3 2.Ra3 Kd4 3.Ra4+ Kc5 4.d4+ Kb6 5.d5 Bh3 6.Kb2 Kc5 7.Ra6 Bd7 8.Kc3 Bb5
9.Rf6 Be8 10.d6 Bd7 11.Bc4
  +-  (6.77)   Depth: 18/31   00:00:12  15564kN, tb=1536
1...Kc3 2.Ra3 Kd4 3.Ra4+ Kc5 4.d4+ Kd6 5.Ra6+ Kc7 6.d5 Kb7 7.d6 Bc6 8.Bc4 Bd7
9.Kb2 Bf5 10.Kc3 Bd7 11.Kd4 Bf5 12.Ra1
  +-  (7.17)   Depth: 19/41   00:00:19  24312kN, tb=3136
1...Kc3 2.Ra3 Kb4 3.Kb2 Kc5 4.d4+ Kd6 5.Ra6+ Kc7 6.d5 Kb7 7.d6 Bc6 8.Ra1 Kb6
9.Be6 Kb7 10.Kc3 Bf3 11.Kd4 Kb6 12.Rb1+ Kc6
  +-  (7.64)   Depth: 20/53   00:00:46  57204kN, tb=11397
1...Kc3 2.Ra3 Kd4 3.Ra4+ Kc5 4.Ra2 Bf1 5.Be6 Kd6 6.Rf2 Kc7 7.Rxf1 Kd6 8.Bb3 Kc6
9.d4 Kb5 10.Kb2 Kb6 11.Bd5 Kc7 12.Kc3
  +-  (10.03)   Depth: 21/59   00:01:05  81560kN, tb=15074
1...Kc3 2.Ra3 Kd4 3.Ra4+ Kc5 4.Ra2 Bf1 5.Be6 Kd6 6.Rf2 Bh3 7.Bxh3 Ke5 8.d4+ Ke4
9.Rd2 Kd5 10.Rd1 Ke4 11.d5 Ke3 12.d6 Ke2 13.Rc1
  +-  (14.06)   Depth: 22/59   00:01:41  127204kN, tb=28020
1...Kc3 2.Ra3 Kd4 3.Ra4+ Kc5 4.Ra2 Bf1 5.Rf2 Bh3 6.Be6 Kb4 7.Bxh3 Kc3 8.d4 Kc4
9.Rd2 Kd5 10.Bg2+ Kd6 11.d5 Kd7 12.d6 Ke8 13.Bc6+ Kd8 14.d7 Kc7 15.d8Q+ Kxc6
  +-  (15.58)   Depth: 23/59   00:02:00  151435kN, tb=33342
1...Kc3 2.Ra3 Kd4 3.Ra4+ Kc5 4.Ra2 Bf1 5.Rf2 Bh3 6.Be6 Kb4 7.Bxh3 Kc3 8.d4 Kc4
9.Be6+ Kb5 10.Rc2 Kb4 11.Rc4+ Kb5 12.d5 Kb6 13.d6 Kb7 14.d7 Ka6 15.d8Q
  +-  (18.81)   Depth: 24/69   00:03:10  238416kN, tb=45277

(,  21.11.2005)

latest private Movei with the same tablebases has no problem because it
translates long mates to a static score that is not mate but material advantage
so it shows 2.54 pawns advantage for white(note that long mate may be translated
to draw by the 50 move rule so I think that it is a bad idea to translate long
mates by nalimov tablebases to mate at least in the case of mate in more than 50
moves).

Uri

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