Author: Bernhard Bauer
Date: 07:29:48 11/30/99
Go up one level in this thread
On November 29, 1999 at 15:11:39, Robert Hyatt wrote:
>On November 29, 1999 at 03:02:23, Paulo Soares wrote:
>
>>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
>
>
>
>This looks _incredibly_ dangerous. For every position where Bxh6 works,
>there are 10 positions where Bxh6 loses. Here a piece for two pawns looks
>awful if the other pieces can't get over to help out... Speculative play is
>nice, as in the old days of the Novag gadgets from Kittinger, and in the current
>play of CSTal... but it can backfire big-time as well...
>
>Crafty doesn't like the sac, unless it sees actual material coming back, because
>I have spent a lot of time teaching it which types of material imbalance are
>bad and which types are good. A piece for 2 pawns is always bad unless there
>is some tactical conclusion at the end. And given the above PV there obviously
>isn't anything except a somewhat naked king position for black...
>
>
Crafty doesn't like the sac? Have you set up the right position?
For me Crafty 17.2 likes the sac from ply 4.
Here some output from Crafty:
3-> 0.06 0.39 1. c3 Bg4 2. c5
4 0.06 0.20 1. c3 Bg4 2. c5 Rd8
4 0.08 0.21 1. Re2 Rd8 2. Qe1 Nd4
1. Rf3 Bg4 2. Rg3 Be2 4 0.08 10/38 1. 4 0.08 0.26 Qe3
4 0.11 ++ 1. Bxh6!!
4 0.11 1.28 1. Bxh6 f6 2. Bf4 Rd8
4-> 0.12 1.28 1. Bxh6 f6 2. Bf4 Rd8
5 0.14 1.42 1. Bxh6 f6 2. Bf4 Bg4 3. c5
5-> 0.15 1.42 1. Bxh6 f6 2. Bf4 Bg4 3. c5
6 0.25 1.31 1. Bxh6 Qd7 2. Be3 Rd8 3. Bg5 f6 <HT>
6-> 0.28 1.31 1. Bxh6 Qd7 2. Be3 Rd8 3. Bg5 f6 <HT>
7 0.59 1.33 1. Bxh6 f6 2. Bf4 Rd8 3. Qe2 Nd4 4.
Qe4
7-> 0.62 1.33 1. Bxh6 f6 2. Bf4 Rd8 3. Qe2 Nd4 4.
Qe4
8 1.37 -- 1. Bxh6
8 2.22 0.66 1. Bxh6 Ne5 2. Qc3 Bxc4 3. Bxc4 gxh6
4. Qg3+ Kh7 5. Bd5
8-> 2.70 0.66 1. Bxh6 Ne5 2. Qc3 Bxc4 3. Bxc4 gxh6
4. Qg3+ Kh7 5. Bd5
9 3.65 ++ 1. Bxh6!!
9 7.26 1.29 1. Bxh6 f6 2. Bf4 Rd8 3. Re1 Bg4 4.
Rxe7 Qxe7 5. Qe3 Rd7
9-> 7.56 1.29 1. Bxh6 f6 2. Bf4 Rd8 3. Re1 Bg4 4.
Rxe7 Qxe7 5. Qe3 Rd7
10 12.65 1.25 1. Bxh6 f6 2. Be3 Qh5 3. b4 Ne5 4.
Bc5 Rd7 5. Rf4 Rad8
10-> 13.67 1.25 1. Bxh6 f6 2. Be3 Qh5 3. b4 Ne5 4.
Bc5 Rd7 5. Rf4 Rad8
11 27.70 1.25 1. Bxh6 f6 2. Be3 Qh5 3. b4 Ne5 4.
Bc5 Ree8 5. Rf4 Nxd3 6. cxd3 Qe5
11-> 31.58 1.25 1. Bxh6 f6 2. Be3 Qh5 3. b4 Ne5 4.
Bc5 Ree8 5. Rf4 Nxd3 6. cxd3 Qe5
12 1:48 1.22 1. Bxh6 f6 2. Bf4 Bg4 3. h3 Bh5 4.
c3 Ne5 5. Bxe5 Rxe5 6. Qf4 Rd8 7. Bf5
time=2:00 cpu=200% mat=0 n=54634283 fh=92% nps=454565
ext-> checks=1816635 recaps=151810 pawns=543 1rep=164628 thrt:3875
predicted=0 nodes=54634283 evals=11753853
endgame tablebase-> probes done=0 successful=0
hashing-> trans/ref=23% pawn=99% used=99%
SMP-> split=314 stop=52 data=7/64 cpu=4:00 elap=2:00
BTW, I changed nothing, no changes in the evaluation none in the extensions.
Kind regards
Bernhard
>
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