Author: Richard Pijl
Date: 02:31:05 11/14/05
Go up one level in this thread
>In this position, White is already in trouble, but 36. Rxe5 looks
>like a mistake. Chess Tiger avoids it immediately, and gives a
>+2 or so plus score for Black after forcing Rxe5. But several other
>programs, including mine, want to play it.
>
>[D] r7/8/3k4/3bppN1/1p1r4/p2PRPP1/1P3K1P/4R3 w - -
The Baron doesn't think Rxe5 is a mistake. It does already show a sound plus for
black though.
Initially it selects bxa3 and switches to Rxe5 after a few seconds. I let it run
for a while and the score didn't drop significantly (Xeon 2.8Ghz, single CPU):
ply time nodes score pv
6(12). 0:00.52 117212 -1.54 b2xa3 b4xa3 Re3xe5 a3-a2 Re5xf5
a2-a1Q Ng5-e4
7(13)& 0:00.66 156068 -1.54 b2xa3 b4xa3 Re3xe5 a3-a2 Re5xf5
a2-a1Q Ng5-e4 Kd6-c7 (Re1xa1)
7(13). 0:01.27 304913 -1.54 b2xa3 b4xa3 Re3xe5 a3-a2 Re5xf5
a2-a1Q Ng5-e4 Kd6-c7 (Re1xa1)
8(14)& 0:01.58 389127 -1.54 b2xa3 b4xa3 Re3xe5 a3-a2 Re5xf5
a2-a1Q Ng5-e4 Kd6-c7 Re1xa1
8(14)& 0:02.06 508399 -1.39 Re3xe5 a3-a2 Re5xf5 Rd4xd3 Rf5-f6
Kd6-d7 Re1-a1 Rd3-b3 (h2-h4)
8(14). 0:02.73 679736 -1.39 Re3xe5 a3-a2 Re5xf5 Rd4xd3 Rf5-f6
Kd6-d7 Re1-a1 Rd3-b3 (h2-h4)
9(15)+ 0:04.36 1099267 -1.04 Re3xe5 (a3-a2) (Re5-e2) (a2-a1Q) (Re1xa1)
(Ra8xa1) (Kf2-e3) (Kd6-c5) (Re2-c2)
9(15)& 0:04.83 1232903 -0.93 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Rd3-d4 (h4-h5)
9(15). 0:05.49 1413154 -0.93 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Rd3-d4 (h4-h5)
10(16)& 0:09.11 2346338 -1.09 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Rd3-d4 Kf2-e3 (Kd6-c5)
10(16). 0:10.14 2627420 -1.09 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Rd3-d4 Kf2-e3 (Kd6-c5)
11(17)& 0:16.55 4390186 -0.92 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Kd6-c5 h4-h5 Ra8-a6
11(17). 0:18.27 4873804 -0.92 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Kd6-c5 h4-h5 Ra8-a6
12(18)& 0:35.64 9466833 -1.26 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Rd3-d4 Kf2-e3 Kd6-c5 Ra1-c1
Rd4-c4
12(18). 0:44.20 11624258 -1.26 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Rd3-d4 Kf2-e3 Kd6-c5 Ra1-c1
Rd4-c4
13(22)& 1:03.45 16887813 -1.19 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
Rd3-d4 f3-f4 b4-b3 h2-h4 Rd4-c4 h4-h5
Ra8-h8
13(22). 1:39.39 26431363 -1.19 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
Rd3-d4 f3-f4 b4-b3 h2-h4 Rd4-c4 h4-h5
Ra8-h8
14(22)& 2:47.72 44887664 -1.39 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
Rd3-d4 Kf2-e3 Kd6-c5 h2-h4 b4-b3 Ke3-f2
(Ra8-a6)
14(24). 4:34.84 74170056 -1.39 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
Rd3-d4 Kf2-e3 Kd6-c5 h2-h4 b4-b3 Ke3-f2
(Ra8-a6)
15(25)& 7:00.93 114425548 -1.39 Re3xe5 a3-a2 Re5-e2 Rd4xd3 Re1-a1
b4-b3 h2-h4 Rd3-d4 Kf2-e3 Kd6-c5 (Ke3-f2)
(Kc5-d6) <rep>
>
>At move 38, we have this position for Black:
>
>[D] r7/8/3k4/3b1pN1/1p6/3r1PP1/pP2RK1P/R7 b - -
>
The Baron is in fact a little instable in its score here. It selects b3
initially, changes to Rd4 after a second with a score increase, then selects b3
back after 20 seconds with another score increase, crossing the +2 mark soon
after:
ply time nodes score pv
7(12)& 0:00.50 130398 +1.26 b4-b3 h2-h4 Rd3-d4 Kf2-e3 Kd6-c5
Ra1-c1 Rd4-c4
7(12). 0:00.53 143699 +1.26 b4-b3 h2-h4 Rd3-d4 Kf2-e3 Kd6-c5
Ra1-c1 Rd4-c4
8(12)& 0:00.78 208606 +1.17 b4-b3 h2-h4 Bd5-c4 f3-f4 Ra8-a7
Ng5-f3 Bc4-d5
8(14)& 0:01.34 364308 +1.19 Rd3-d4 f3-f4 b4-b3 h2-h4 Rd4-c4
h4-h5 Ra8-h8
8(14). 0:01.42 389504 +1.19 Rd3-d4 f3-f4 b4-b3 h2-h4 Rd4-c4
h4-h5 Ra8-h8
9(15)& 0:02.78 767815 +1.39 Rd3-d4 Kf2-e3 Kd6-c5 h2-h4 b4-b3
Ke3-f2 Ra8-a6 h4-h5 (Rd4-c4)
9(15). 0:02.89 800471 +1.39 Rd3-d4 Kf2-e3 Kd6-c5 h2-h4 b4-b3
Ke3-f2 Ra8-a6 h4-h5 (Rd4-c4)
10(16)& 0:06.69 1868063 +1.36 Rd3-d4 Kf2-e3 Rd4-c4 Ke3-d3 b4-b3
h2-h4 Ra8-c8 h4-h5 Rc4-c1
10(16). 0:07.84 2198505 +1.36 Rd3-d4 Kf2-e3 Rd4-c4 Ke3-d3 b4-b3
h2-h4 Ra8-c8 h4-h5 Rc4-c1
11(18)& 0:13.05 3681835 +1.51 Rd3-d4 f3-f4 b4-b3 Ng5-f3 Rd4-c4
h2-h3 Ra8-h8 Nf3-h4 Rh8-f8 Nh4-f3
11(18)+ 0:19.94 5641838 +1.71 b4-b3 (h2-h4) (Rd3-d4) (Kf2-e3) (Rd4-c4)
(h4-h5) (Ra8-e8) (Ke3-d3) (Re8xe2)
(Kd3xe2) (Rc4-c2)
11(18)& 0:26.81 7585428 +2.27 b4-b3 h2-h4 Ra8-c8 Kf2-e1 Rc8-c7
Ke1-f2 Rc7-c2 Kf2-e1 Bd5xf3 Ng5xf3 Rd3xf3
Ra1-d1 (Kd6-c5)
11(18). 0:27.00 7655509 +2.27 b4-b3 h2-h4 Ra8-c8 Kf2-e1 Rc8-c7
Ke1-f2 Rc7-c2 Kf2-e1 Bd5xf3 Ng5xf3 Rd3xf3
Ra1-d1 (Kd6-c5)
12(21)- 0:51.28 14556556 +1.92 b4-b3
12(21)& 1:07.61 19128519 +2.27 b4-b3 h2-h3 Ra8-g8 h3-h4 Rg8-c8
(Kf2-e1) (Rc8-c7) (Ke1-f2) (Rc7-c2)
(Kf2-e1) (Rc2-c8)
(Ke1-f2) (Rc8-c2) <rep>
12(21). 1:07.61 19128553 +2.27 b4-b3 h2-h3 Ra8-g8 h3-h4 Rg8-c8
(Kf2-e1) (Rc8-c7) (Ke1-f2) (Rc7-c2)
(Kf2-e1) (Rc2-c8)
(Ke1-f2) (Rc8-c2) <rep>
13(21)+ 1:39.27 28240658 +2.62 b4-b3 (h2-h3) (Ra8-g8) (h3-h4) (Rg8-c8)
(Kf2-e1) (Bd5xf3) (Ng5xf3) (Rd3xf3)
(Ra1-d1) (Kd6-c6)
(Re2-e6) (Kc6-b5) (Re6-e5) (Kb5-b4)
(Ke1-e2) (Rf3xg3)
13(21)& 1:51.70 31789977 +2.53 b4-b3 h2-h3 Rd3-d4 f3-f4 Rd4-d3
h3-h4 Ra8-c8 h4-h5 Rc8-h8 Re2-e3 Rd3-d2
Re3-e2 Rd2-c2 (Re2xc2) (b3xc2)
13(22). 3:07.89 52957178 +2.53 b4-b3 h2-h3 Rd3-d4 f3-f4 Rd4-d3
h3-h4 Ra8-c8 h4-h5 Rc8-h8 Re2-e3 Rd3-d2
Re3-e2 Rd2-c2 (Ng5-f3)
14(23)& 5:09.57 86633186 +2.82 b4-b3 h2-h4 Rd3-d4 f3-f4 Rd4-d3
h4-h5 Ra8-h8 Re2-e3 Rd3-d2 Re3-e2 Rd2xe2
Kf2xe2 Rh8xh5 Ng5-f3 Rh5-h7 Ke2-e3
14(23). 5:47.54 97198674 +2.82 b4-b3 h2-h4 Rd3-d4 f3-f4 Rd4-d3
h4-h5 Ra8-h8 Re2-e3 Rd3-d2 Re3-e2 Rd2xe2
Kf2xe2 Rh8xh5 Ng5-f3 Rh5-h7 Ke2-e3
btw, the analysis above is all with clean hashtables, and _not_ on the same
machine that played this game on ICC. That was the dual version, on a Dual AMD
MP 2000+ (with more hash and more EGTB's).
Richard.
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