Author: Dieter Buerssner
Date: 13:14:19 08/18/01
Go up one level in this thread
On August 18, 2001 at 15:18:32, Sune Larsson wrote:
> 8/pR4pk/1b6/2p5/N1p5/8/PP1r2PP/6K1 b - - 0 1
>
> Ortueta - Sanz, 1934
Nice to see this position. It was sent to me by Carlos Pesce, who is also a
regular at this forum, perhaps almost a year ago.
My current developement version of Yace, AMD K6-2 475, 20M hash needs 1:45:
1497226 9.701 -0.12 9. 1...c3 2.bxc3 Rxa2 3.Nxb6 axb6 4.Rxb6 Ra3 5.Rc6
Rxc3
1693487 10.698 -0.22 10t 1...c3 2.bxc3 Rxa2 3.Nxb6 axb6 4.Rxb6 Ra3 5.c4
Rc3 6.Rc6 Rxc4 7.Kf2 Rc3H 8.g4H {HT}
1946017 12.217 -0.21 10t+ 1...Bd8 2.Rxa7 Bf6 3.Rb7 Bd4+ 4.Kf1 Rf2+ 5.Ke1
Rxg2 6.Nxc5 Bxc5 7.Rb5 {270}
2458940 15.380 -0.11 10t 1...Bd8 2.Rxa7 Bf6 3.Rb7 Bd4+ 4.Kf1 Rf2+ 5.Ke1
Rxg2 6.h3 Rh2 7.Rb5 g6 {10}
2926399 18.128 -0.11 10. 1...Bd8 2.Rxa7 Bf6 3.Rb7 Bd4+ 4.Kf1 Rf2+ 5.Ke1
Rxg2 6.h3 Rh2 7.Rb5 g6 {10}
4866538 30.034 -0.10 11t 1...Bd8 2.Rxa7 Bf6 3.Rb7 Bd4+ 4.Kf1 Rf2+ 5.Ke1
Rxg2 6.h3 Rh2 7.Rb5 Kg6 8.h4 {10}
6251300 38.072 -0.10 11. 1...Bd8 2.Rxa7 Bf6 3.Rb7 Bd4+ 4.Kf1 Rf2+ 5.Ke1
Rxg2 6.h3 Rh2 7.Rb5 Kg6 8.h4 {10}
13214562 1:21.1 -0.09 12t 1...Bd8 2.h3 Bf6 3.Kf1 Bd4 4.g3 Rf2+ 5.Ke1 a6
6.Ra7 Rh2 7.Rxa6 Bxb2 8.Nxb2 Rxb2 {HT} {0}
17224255 1:44.6 -0.08 12t+ 1...Rxb2 2.Nxb2 c3 3.Rxb6 c4 4.Rb4 a5 5.Rxc4
cxb2 6.Rh4+ Kg6 7.Kf2 b1=Q 8.Kf3 {421}
17819072 1:47.9 0.30 12++ 1...Rxb2 2.Nxb2 c3 3.Rxb6 c4 4.Rb4 a5 5.Rxc4
cxb2 6.Rh4+ Kg6 7.Kf2 b1=Q 8.Kf3 {421}
20309569 2:02.6 1.56 12t 1...Rxb2 2.Nxb2 c3 3.Rxb6 c4 4.Rb4 a5 5.Nd3
cxd3 6.Rh4+ Kg8 7.Rc4 d2 8.Rc8+ Kf7 9.Rd8 {-420}
20518471 2:03.9 1.56 12. 1...Rxb2 2.Nxb2 c3 3.Rxb6 c4 4.Rb4 a5 5.Nd3
cxd3 6.Rh4+ Kg8 7.Rc4 d2 8.Rc8+ Kf7 9.Rd8 {-420}
27089623 2:42.1 1.89 13t 1...Rxb2 2.Nxb2 c3 3.Rxb6 c4 4.Rb4 a5 5.Rb5 c2
6.Kf2 c1=Q 7.Ke2 Qg1 8.Kf3 {HT} {161}
29913694 2:58.8 1.89 13. 1...Rxb2 2.Nxb2 c3 3.Rxb6 c4 4.Rb4 a5 5.Rb5 c2
6.Kf2 c1=Q 7.Ke2 Qg1 8.Kf3 {HT} {161}
Some versions of Yace find it at depth 11 in about 35 seconds on my computer.
It gave me already a lot of headache, why this is the case (after investigagint
MB long dumps of the search tree) ...
I add a snippet of the PGN, Carlos sent. I think, he won't mind:
---
{THE IMPORTANCE OF A PASSED PAWN
This ending was played by two unknown spanish players (Ortueta-Sanz)
but...they seemed the best!}
[Event "?"]
[Site "?"]
[Date "?"]
[Round "-"]
[White "?"]
[Black "?"]
[Result "*"]
[FEN "8/pR4pk/1b6/2p5/N1p5/8/PP1r2PP/6K1 b - - 0 1"]
[SetUp "1"]
{--------------
. . . . . . . .
p R . . . . p k
. b . . . . . .
. . p . . . . .
N . p . . . . .
. . . . . . . .
P P . r . . P P
. . . . . . K .
black to play
--------------}
1... Rxb2 {!!} 2. Nxb2 c3 3. Rxb6 {unique! 3. Nd3? c4+ 4. Rxb6 cxd3 5. Rc6
d2!} c4 {!! see! R and N can't detain the pawn} 4. Rb4 a5
*
{Now, thanks to a passed pawn, white can draw in a difficult position:
Black threaten Qxf4 and Qb1+-Qxb4 or Qb1+-Nf1+}
---
I wonder about one thing. Carlos calls these two unknown players. How is it
possible, that you both found this position independently?
Regards,
Dieter
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