Author: Paulo Soares
Date: 00:02:23 11/29/99
Go up one level in this thread
On November 29, 1999 at 00:32:17, Peter McKenzie wrote:
>The following position is from a blitz game between Hossa and Beadle (LambChop)
>on ICC:
>
>r3q1k1/ppp1rpp1/2n1b2p/8/2P2B2/3B4/PPPQ1RPP/5RK1 w - -
>
>Hossa played Bxh6 and wiped Beadle out. This position is an interesting test of
>king safety evaluation, as there is no short range mate or win of material after
>the sac although I'm pretty confident the sac is correct.
>
>I tried this position with LambChop, and it too liked Bxh6 giving it a score of
>about +0.5 pawns from depths 4 thru 8. On depths 9-10 it switched to Qc3 with a
>similar score of around +0.5, then at depth 11 it switched back to Bxh6 and the
>score jumps to +1.4. Depth 12 is still Bxh6 at +1.6.
>
>We discussed this position a bit on ICC, Bob ran it on Crafty which didn't want
>to play Bxh6. Peter Kappler ran it on Hiarcs which liked Bxh6 straight away
>with a +1 score! Diep also liked Bxh6 from early on, and had an even higher
>score. I wonder what Hiarcs and Diep are doing in eval that Crafty isn't... or
>vice-versa.
>
>How about other programs?
>What do the human chess experts think?
>
>If that position is too hard, it might be productive to play down the main line
>of accepting the sacrifice. So after 1.Bxh6 gxh6 2.Qxh6 we have:
>
>r3q1k1/ppp1rp2/2n1b2Q/8/2P5/3B4/PPP2RPP/5RK1 b - -
>
>Here LambChop gets a score jump from -0.2 at ply 7 to -1.7 at ply 8. Not quite
>sure why :-)
>
>cheers,
>Peter
I agree with you, this is a valid sacrifice.
Rebel Century(note that anti-GM=stronger)- PIII-450
First Position:
+---+---+---+---+---+---+---+---+
8 | *R| | | | *Q| | *K| |
+---+---+---+---+---+---+---+---+ 00:00:00 00:00:00
7 | *p| *p| *p| | *R| *p| *p| |
+---+---+---+---+---+---+---+---+
6 | | | *N| | *B| | | *p| Time infinite
+---+---+---+---+---+---+---+---+ Hash 60 Mb
5 | | | | | | | | | Engine Rebel Century
+---+---+---+---+---+---+---+---+ Personality Rebel Century
4 | | | p | | | B | | | anti-GM Strong
+---+---+---+---+---+---+---+---+ System Tiger Off
3 | | | | B | | | | | Combination Off
+---+---+---+---+---+---+---+---+ Style Normal
2 | p | p | p | Q | | R | p | p | Strength Strongest
+---+---+---+---+---+---+---+---+ Search Normal Search
1 | | | | | | R | K | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
r3q1k1/ppp1rpp1/2n1b2p/8/2P2B2/3B4/PPPQ1RPP/5RK1 w - -
[Event "?"]
[Site "?"]
[Date "??.??.????"]
[Round "?"]
[White "Peter3"]
[Black ""]
[Result "*"]
[WhiteElo "?"]
[BlackElo "?"]
[FEN "r3q1k1/ppp1rpp1/2n1b2p/8/2P2B2/3B4/PPPQ1RPP/5RK1 w - - 0 1"]
1.*
00:00:00 1.00 1.02 1.Bxh6 gxh6 2.Qxh6
00:00:00 2.00 0.43 1.Bxh6 gxh6 2.Qxh6 f5 3.Bxf5 Bxc4
00:00:00 3.00 0.62 1.Bxh6 gxh6 2.Qxh6 f5 3.Bxf5
00:00:00 4.00 1.18 1.Bxh6 f6 2.Be3 Rd8
00:00:01 5.00 1.05 1.Bxh6 gxh6 2.Qxh6 f5 3.Bxf5 Bxc4
4.Bg6 Qd7 (0)
00:00:02 6.00 1.11 1.Bxh6 f6 2.Be3 Ne5 3.Qc3 Nxd3 4.Qxd3
Rd8 (1)
00:00:06 7.00 1.02 1.Bxh6 gxh6 2.Qxh6 f5 3.Bxf5 Bxc4
4.Bg6 Qd8 5.Rd2 (4)
00:00:28 8.00 1.10 1.Bxh6 f6 2.Be3 Rd7 3.Qc3 Rad8 4.b4
Qh5 (13)
00:01:27 9.00 1.28 1.Bxh6 f6 2.Rxf6 gxf6 3.Rxf6 Qd7
4.Qg5+ Kh8 5.Bf8 Rh7 6.Bxh7 (41)
00:04:09 10.00 1.26 1.Bxh6 f6 2.Rxf6 gxf6 3.Rxf6 Qd7
4.Qg5+ Kh8 5.Bf8 Qd4+ 6.Kh1 Rh7 (135)
00:20:39 11.00 1.71 1.Bxh6 Qf8 2.Qg5 Rd7 3.Rf3 Rad8
Positions : 182.640.681
Nodes per second : 136.502
Extensions (checks) : 7.804.673 (4%)
Extensions (captures) : 3.739.854 (2%)
Extensions (king safety) : 701.204 (0%)
Extensions (on depth) : 5.358.611 (2%)
Extensions (remaining) : 162.555 (0%)
Extensions (total) : 17.766.898 (9%)
Hash Table : 1.517.447 1.188.944 (99%)
Average depth : 12
Deepest depth : 53
Second position:
+---+---+---+---+---+---+---+---+
8 | *R| | | | *Q| | *K| |
+---+---+---+---+---+---+---+---+ 00:00:00 00:00:00
7 | *p| *p| *p| | *R| *p| | |
+---+---+---+---+---+---+---+---+
6 | | | *N| | *B| | | Q | Time infinite
+---+---+---+---+---+---+---+---+ Hash 60 Mb
5 | | | | | | | | | Engine Rebel Century
+---+---+---+---+---+---+---+---+ Personality Rebel Century
4 | | | p | | | | | | anti-GM Strong
+---+---+---+---+---+---+---+---+ System Tiger Off
3 | | | | B | | | | | Combination Off
+---+---+---+---+---+---+---+---+ Style Normal
2 | p | p | p | | | R | p | p | Strength Strongest
+---+---+---+---+---+---+---+---+ Search Normal Search
1 | | | | | | R | K | |
+---+---+---+---+---+---+---+---+
a b c d e f g h
r3q1k1/ppp1rp2/2n1b2Q/8/2P5/3B4/PPP2RPP/5RK1 b - -
[Event "?"]
[Site "?"]
[Date "??.??.????"]
[Round "?"]
[White "Peter10"]
[Black ""]
[Result "*"]
[WhiteElo "?"]
[BlackElo "?"]
[FEN "r3q1k1/ppp1rp2/2n1b2Q/8/2P5/3B4/PPP2RPP/5RK1 b - - 0 1"]
1..*
00:00:00 1.00 -3.50 1..Bxc4 2.Bxc4
00:00:00 1.01 -0.98 1..Nd4
00:00:00 1.03 -0.89 1..Rd8
00:00:00 1.18 -0.85 1..Qf8
00:00:00 1.24 -0.13 1..f5 2.Bxf5 Bxc4
00:00:00 2.00 -0.85 1..f5 2.Bxf5 Bxc4 3.Bg6 Qd7
00:00:00 3.00 -0.58 1..f5 2.Bxf5 Bxc4
00:00:00 4.00 -0.45 1..f5 2.Bxf5 Bxc4 3.Bg6 Qc8 4.Ra1
Nd4 (0)
00:00:00 5.00 -0.72 1..f5 2.Bxf5 Bxc4 3.Bg6 Qd8 4.Rd2
00:00:01 6.00 -1.46 1..f5 2.Bxf5 Bxf5 3.Rxf5 Re5 4.Rf6
Qd7 (1)
00:00:09 7.00 -1.89 1..f5 2.Bxf5 Nd4 3.Bd3 Nc6 4.Bg6
Qd8 (5)
00:00:21 8.00 -2.63 1..f5 2.Bxf5 Nd4 3.Bd3 Rg7 4.c3
Nc6 5.Rf8+ Qxf8 6.Qxe6+ Rf7 7.Qg6+
Rg7 (12)
00:00:45 9.00 -3.00 1..f5 2.Bxf5 Nd4 3.Bd3 c5 4.Rf6
Rg7 5.c3 (36)
00:01:15 10.00 -3.27 1..f5 2.Bxf5 Nd4 3.Bd3 Rg7 4.Rf4
Rd8 (56)
00:03:21 11.00 -3.03 1..f5 2.Bxf5 Nd4 3.Bd3 Rg7 4.c3
Nc6 5.Rf8+ Qxf8 6.Qxe6+ Kh8 7.Rxf8+ (133)
Positions : 24.825.096
Nodes per second : 118.780
Extensions (checks) : 3.893.161 (15%)
Extensions (captures) : 427.768 (1%)
Extensions (king safety) : 121.776 (0%)
Extensions (on depth) : 269.512 (1%)
Extensions (remaining) : 27.516 (0%)
Extensions (total) : 4.739.733 (19%)
Hash Table : 470.761 688.827 (84%)
Average depth : 13
Deepest depth : 58
Paulo Soares, from Brazil
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Last modified: Thu, 15 Apr 21 08:11:13 -0700
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