interesting sac

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jdart
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interesting sac

Post by jdart »

This occured in a game Arasan-Xyclops on ICC:

[d] 5r1k/4q1pp/8/5P2/4n3/5Q1P/PPP2P2/R1Br1BK1 b - - 0 25

here Xyclops played Nxf2. I think this is not a bad move, but I'm not clear it's best either. Fritz and Shredder prefer .. Re1, at least initially. Fritz eventually switches to Nxf2 with a small advantage for Black. How you score this will depend on eval of uneven material and passed pawns, among other things.

The resulting endgame after .. Nxf2 is hard for White to defend. Arasan made a few inaccurate moves but I didn't see a real blunder.

Btw. I have very little info about Xyclops but it is doing well on ICC. I think Arasan has won against it only once and that was helped by book knowledge.
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Eelco de Groot
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Re: interesting sac

Post by Eelco de Groot »

Thanks for the position Jon. A good testposition! Ancalagon does not play Nxf2, only after preparing it first with Qh4. But I think that is a different combination, because now the Knight is defended at least once after taking the pawn. After a while the search seems to suggest exchanging Queens is not the best way to defend for White. I have not checked other engines yet, I am a bit worried that none of the programs you mention have Qe7-h4 in mind, it seems such an obvious move but then again the search is very experimental so could be very wrong. The eval could be pretty lopsided as well though because of the (1000/256)*(100/256) values for King Safety compared with the normal Glaurung. But I do not really want to change that yet...


[d]5r1k/4q1pp/8/5P2/4n3/5Q1P/PPP2P2/R1Br1BK1 b - -

Engine: Ancalagon 2.0 Beta 006j settings Build 69 (Athlon 2009 MHz, 256 MB)
by Tord Romstad, Eelco de Groot

2.00 0:00 -1.80 1...Rfd8 2.Qh5 (255) 0

2.00 0:00 -1.74 1...Rd5 2.Bd3 (388) 1

3.00 0:00 -1.96 1...Rd5 2.Bd3 Rd4 (848) 2

3.00 0:00 -1.50 1...Rfd8 2.Qf4 Kg8 (1.409) 4

3.00 0:00 -0.70 1...Re1 2.Qa3 Qxa3 3.bxa3 Rxf5 (1.850) 5

4.00 0:00 -0.70 1...Re1 2.Qa3 Qxa3 3.bxa3 Rxf5 (3.017) 9

5.00 0:00 -0.82 1...Re1 2.Qa3 Qxa3 3.bxa3 Rxf5 4.f4 (5.728) 16

5.00 0:00 -0.43 1...Rfd8 2.Qf4 Nd2 3.Bxd2 Rxa1 4.a4 (9.392) 26

6.00 0:00 -0.13 1...Rfd8 2.b4 Qh4 3.Bb2 R1d2 4.Qg2 (16.071) 42

7.00 0:00 +0.15 1...Rfd8 2.b4 Qh4 3.Bb2 R1d2 4.Be2 Rxc2 (74.581) 132

8.00 0:00 +0.09 1...Rfd8 2.b4 Qh4 3.Bb2 R1d2 4.Be2 Rxc2
5.Be5 (106.463) 162

9.00 0:01 -0.17 1...Rfd8 2.c4 Qh4 3.Qg2 R8d3 4.Kh2 Rd8
5.f6 Nxf6 (379.143) 278

9.02 0:01 +0.19 1...Qh4 2.b4 Rc8 3.Qg2 Rxc2 4.Bg5 Rxf1+
5.Rxf1 Qxg5 6.Qxg5 Nxg5 7.a4 Nxh3+
8.Kg2 (523.632) 294

10.01 0:02 +0.39 1...Qh4 2.b4 Rc8 3.Qg2 Rxc2 4.Bg5 Rxf1+
5.Rxf1 Qxg5 6.Qxg5 Nxg5 7.a4 Nxh3+
8.Kg2 Nf4+ 9.Kf3 (840.084) 320

11.01 0:07 +0.41 1...Qh4 2.Kg2 Re1 3.Bd3 Nd2 4.Qg3 Qe7
5.c4 Qb7+ 6.f3 Rd1 7.c5 (2.531.956) 354

12.01 0:14 +0.47 1...Qh4 2.Kg2 Re1 3.Bd3 Nd2 4.Bxd2 Rxa1
5.Qf4 Qf6 6.Bc1 Rxa2 7.b4 Rd8 (5.466.223) 367

13.01 1:14 +2.19 1...Qh4 2.b4 Nxf2 3.Qxf2 Qxf2+
4.Kxf2 Rxf5+ 5.Ke3 Rfxf1 6.b5 Rxc1
7.Rxc1 Rxc1 8.Kd2 Rh1 9.b6 Rh2+
10.Kd3 Rxh3+ 11.Kd4 (28.283.624) 378

14.01 1:46 +2.60 1...Qh4 2.b4 Nxf2 3.Qxf2 Qxf2+
4.Kxf2 Rxf5+ 5.Ke3 Rfxf1 6.a4 Rxc1
7.Rxc1 Rxc1 8.b5 Rxc2 9.b6 Kg8 10.b7 Rb2 (40.316.049) 379

15.01 2:28 +2.70 1...Qh4 2.b4 Nxf2 3.Qxf2 Qxf2+
4.Kxf2 Rxf5+ 5.Ke3 Rfxf1 6.c4 Rfe1+
7.Kf3 Rxc1 8.Rxc1 Rxc1 9.c5 Rc3+
10.Kg2 Rc4 11.a3 Rc2+ 12.Kf3 Rc3+
13.Ke4 Rxa3 (56.528.474) 381

16.01 4:32 +2.56 1...Qh4 2.Kg2 Nxf2 3.Be2 Rh1 4.Bf4 Rxa1
5.Qxf2 Qd8 6.Bd3 Qd5+ 7.Kg3 Rxa2
8.Qf3 Qd4 9.Be3 Qxb2 10.Kg2 (104.044.369) 382

17.01 8:55 +2.54 1...Qh4 2.Kg2 Nxf2 3.Be2 Rh1 4.Bf4 Rxa1
5.Qxf2 Qd8 6.Bd3 Re8 7.h4 Rxa2 8.b4 Ra1
9.Kh2 Qe7 10.b5 (203.648.768) 379

18.01 23:27 +2.49 1...Qh4 2.Kg2 Nxf2 3.Be2 Rh1 4.Bf4 Rxa1
5.Qxf2 Qd8 6.Bd3 Qd5+ 7.Kg3 Qh1
8.Kh4 Rxa2 9.b4 Ra4 10.Qf1 Qxf1
11.Bxf1 Rxb4 (518.542.341) 368

best move: Qe7-h4 time: 29:16.656 min n/s: 370.589 nodes: 650.970.000

It is a strange material composition, White's Bishop pair and four pawns against Black's Rook and Knight, White gets big bonuses for the passed pawns to offset its King Safety but not enough here so I think its King Safety score must be real bad...

Eelco
Debugging is twice as hard as writing the code in the first
place. Therefore, if you write the code as cleverly as possible, you
are, by definition, not smart enough to debug it.
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jdart
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Re: interesting sac

Post by jdart »

I think Glaurung is right - Qh4 first with the followup Nxf2 wins.

On my Athlon dual, Deep Shredder 10 switches to Qh4 after 88 seconds:

no 4 80 +59 6036 Re1 Qf4
no 5 80 +34 7337 Re1 Qf4
no 5 80 +26 9884 Re1 Qf4 Rc8 f6 Nxf6
no 6 90 +35 26276 Re1 Qf4 Qb7 c4 Nc5 a4
no 7 160 +60 72014 Re1 Qf4
no 7 160 +64 77613 Re1 Qf4 Nd6 Qg4 Rxf5 c4 Kg8
no 8 220 +41 134888 Re1 Qf4 Qd7
no 9 330 +66 248851 Re1 Qf4
no 9 380 +66 283098 Re1 Qf4
no 10 890 +74 793926 Re1 Qg4 Rd8 Bg5 Rxf1+ Kxf1 Nxg5
no 11 1340 +74 1246263 Re1 Qg4 Qf6 c4 Nd2 Bxd2 Rxa1 Bc3 Qe7
no 12 2550 +72 2453318 Re1 Qg4 Qf6 c4 Qe5 Bf4 Qxb2 Rxe1 Qxf2+
Kh1 Qxe1 Qe2 Nf2+ Kh2
no 13 7220 +63 7102174 Re1 Qg4 Qc7 Bf4 Qxc2 Rxe1 Qxf2+ Kh1 Qxe1
Qe2 Qb1 Qc4 Nf2+ Kg2 Qxb2 Qe2 Qxe2 Bxe2
no 14 16340 +55 16496373 Re1 b4 Nd2 Bxd2 Rxa1 c4 Rxa2 Bc3 Qg5+ Qg3
Rxf5 Bg2 Qe7 Bd4 Rd2 Be4
no 15 25450 +55 26117454 Re1 b4 Nd2 Bxd2 Rxa1 c4 Rxa2 Bc3 Qg5+ Qg3
Rxf5 Bg2 Qe7 Bd4 Rd2 Be4
no 16 68330 +41 70261971 Re1 b3 Nd2 Bxd2 Rxa1 a4 Ra2 Bd3 Qf6 Kg2
Re8 Qd5
yes 16 88020 +42 90854169 Qh4
yes 16 104920 +77 107752627 Qh4
yes 16 176420 +161 180811434 Qh4 Kg2 Nxf2 Be2 Rh1 Qe3
yes 17 262810 +136 269860575 Qh4 Kg2
yes 17 314800 +136 321084559 Qh4 Kg2
yes 18 497520 +160 514213969 Qh4 Kg2 Nxf2 a3 Ne4
yes 19 957970 +184 982065831 Qh4 Kg2 Nxf2 a4 Ne4
Audmeister
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Re: interesting sac

Post by Audmeister »

yes, xyclops is doing quite well on ICC, I think TwistedLogic has only beaten it a couple times out of many.

xyclops is also doing well in the ChessWar XII B 40m/30' http://www.open-aurec.com/chesswar/Chesswar012BSt.htm

This program is quite strong.
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Dr.Wael Deeb
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Re: interesting sac

Post by Dr.Wael Deeb »

Audmeister wrote:yes, xyclops is doing quite well on ICC, I think TwistedLogic has only beaten it a couple times out of many.

xyclops is also doing well in the ChessWar XII B 40m/30' http://www.open-aurec.com/chesswar/Chesswar012BSt.htm

This program is quite strong.
And taking into consideration that it plays with one eye only :lol:
_No one can hit as hard as life.But it ain’t about how hard you can hit.It’s about how hard you can get hit and keep moving forward.How much you can take and keep moving forward….
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AdminX
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Re: interesting sac

Post by AdminX »

Dr.Wael Deeb wrote:
Audmeister wrote:yes, xyclops is doing quite well on ICC, I think TwistedLogic has only beaten it a couple times out of many.

xyclops is also doing well in the ChessWar XII B 40m/30' http://www.open-aurec.com/chesswar/Chesswar012BSt.htm

This program is quite strong.
And taking into consideration that it plays with one eye only :lol:


:lol: :lol: :lol:
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Eelco de Groot
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Re: interesting sac

Post by Eelco de Groot »

Hi Jon, maybe Qh4 is winning but Naum 3.1 is not certain, I sometimes suspect Naum not to do any King Safety evaluation or else its eval could be based upon Rybka's where +1.0 usually means very good winning chances, well maybe I'm exaggerating a bit here. But Naum chooses yet another move!


[d]5r1k/4q1pp/8/5P2/4n3/5Q1P/PPP2P2/R1Br1BK1 b - -

Engine: Naum 3.1 (single core Athlon 2009 MHz, 256 MB)
by Aleksandar Naumov

1/12 0:00 -0.07 1...Qh4 (1.240) 82

2/14 0:00 -0.18 1...Rxc1 2.Rxc1 (3.684) 245

3/12 0:00 -0.18 1...Rxc1 2.Rxc1 Qg5+ (4.810) 155

3/12 0:00 -0.15 1...Rfd8 2.a4 Rxc1 (6.161) 198

4/13 0:00 -0.15 1...Rfd8 2.a4 Rxc1 3.Rxc1 (7.643) 246

5/13 0:00 -0.15 1...Rfd8 2.a4 Rxc1 3.Rxc1 Qg5+ (14.891) 316

6/21 0:00 -0.06 1...Rfd8 2.a4 Qb7 3.Qe2 Qd5 4.Qb5 (50.298) 644

7/23 0:00 -0.48 1...Rfd8 2.b3 Qh4 3.Bb2 R1d2 4.Qg2 R8d7 (129.623) 753

7/23 0:00 -0.28 1...Rxc1 2.Rxc1 Qg5+ 3.Qg2 Qxc1
4.Qxe4 Qxb2 (140.579) 751

7/23 0:00 -0.06 1...Re1 2.Kg2 Nd2 3.Bxd2 Rxa1 4.Bc4 Qc5 (436.589) 822

8/22 0:00 +0.02 1...Re1 2.a4 Qd7 3.Ra3 Qc8 4.Re3 Rxf5
5.Rxe1 (617.728) 807


9/21 0:00 +0.09 1...Re1 2.a4 Nd2 3.Bxd2 Rxa1 4.a5 Qc5
5.b4 Qxc2 (768.820) 833


10/27 0:01 +0.09 1...Re1 2.Kg2 Nd2 3.Bxd2 Rxa1 4.a3 Qe5
5.b4 Ra2 6.Bc3 (1.346.412) 870


11/22 0:02 +0.08 1...Re1 2.Kg2 Nd2 3.Bxd2 Rxa1 4.a3 Qf6
5.b4 Ra2 6.Bd3 Rxa3 (1.781.875) 884


12/23 0:03 +0.13 1...Re1 2.Kg2 Nd2 3.Bxd2 Rxa1 4.a3 Qf6
5.Bc4 Qxb2 6.Bc3 Qxc2 7.Bxa1 (3.107.060) 920


13/27 0:06 +0.12 1...Re1 2.Kg2 Nd2 3.Bxd2 Rxa1 4.a3 Ra2
5.Bc3 Qg5+ 6.Qg3 Rxf5 7.Bc4 Ra1 (5.652.932) 932


14/31 0:19 +0.10 1...Re1 2.b4 Nd2 3.Bxd2 Rxa1 4.Kg2 Rxa2
5.Bd3 Rd8 6.b5 Qf6 7.Qe4 Ra1 8.Bf4 (18.679.259) 949


14/36 0:26 +0.53 1...Qh4 2.Kg2 Nxf2 3.a4 Ne4 4.Bf4 Rxa1
5.Qxe4 Re1 6.Qf3 Qf6 7.Bd2 Ra1 8.b3 (25.230.260) 954


15/32 0:31 +0.44 1...Qh4 2.Kg2 Nxf2 3.a4 Nxh3 4.Qxd1 Rxf5
5.Qe2 Rf2+ 6.Qxf2 Qxf2+ 7.Kxh3 Qxf1+
8.Kg3 Qe1+ (30.384.856) 968


16/32 0:39 +0.43 1...Qh4 2.Kg2 Nxf2 3.a4 Nxh3 4.Qxd1 Rxf5
5.Qe2 Rf2+ 6.Qxf2 Qxf2+ 7.Kxh3 Qxf1+
8.Kg3 Qe1+ 9.Kf3 (39.300.574) 992


17/34 0:55 +0.36 1...Qh4 2.Kg2 Nxf2 3.a4 Nxh3 4.Qxd1 Rxf5
5.Qe2 Rf2+ 6.Qxf2 Qxf2+ 7.Kxh3 Qxf1+
8.Kg3 Qe1+ 9.Kf3 Qd1+ (57.045.293) 1019


18/36 1:29 +0.39 1...Qh4 2.Kg2 Nxf2 3.a4 Ne4 4.Bf4 Rxa1
5.Qxe4 Re1 6.Qf3 Qf6 7.Bd2 Ra1 8.b3 Qxf5
9.Qxf5 Rxf5 10.Bd3 (92.861.660) 1042


19/37 2:23 +0.37 1...Qh4 2.Kg2 Nxf2 3.a4 Ne4 4.Bf4 Rxa1
5.Qxe4 Re1 6.Qf3 Qe7 7.Bd3 Re8 8.Bg3 Ra1
9.b3 Qg5 10.Qf4 Qd8 (152.416.689) 1061


19/45 4:01 +0.57 1...Nxf2 2.Kxf2 Qc5+ 3.Kg2 Qxc2+
4.Qe2 Rxc1 5.Rxc1 Qxc1 6.a3 Qg5+
7.Qg4 Rxf5 8.Qxg5 Rxg5+ 9.Kf3 Rf5+
10.Ke2 Kg8 (252.286.829) 1044 TB:84


20/50 5:50 +0.57 1...Nxf2 2.Kxf2 Qc5+ 3.Kg2 Qxc2+
4.Qe2 Rxc1 5.Rxc1 Qxc1 6.a3 Qg5+
7.Qg4 Rxf5 8.Qxg5 Rxg5+ 9.Kf3 Rf5+
10.Ke2 g6 11.Bg2 (361.803.732) 1031 TB:230


21/43 9:37 +0.59 1...Nxf2 2.Kxf2 Qc5+ 3.Kg2 Qxc2+
4.Qe2 Rxc1 5.Rxc1 Qxc1 6.a3 Qg5+
7.Qg4 Rxf5 8.Qxg5 Rxg5+ 9.Kf3 Rf5+
10.Ke2 Ra5 11.Ke3 g6 (594.303.012) 1029 TB:533


22/47 17:32 +0.68 1...Nxf2 2.Kxf2 Qc5+ 3.Kg2 Qxc2+
4.Qe2 Rxc1 5.Rxc1 Qxc1 6.b4 Qg5+
7.Qg4 Qd2+ 8.Be2 Re8 9.Kf1 Qc1+
10.Kg2 Qb2 11.Kf2 Qxa2 12.b5 (1.080.593.739) 1026
TB:1.630


23/47 28:58 +0.48 1...Nxf2 2.Kxf2 Qc5+ 3.Kg2 Qxc2+
4.Qe2 Rxc1 5.Qxc2 Rxc2+ 6.Kg1 Rxb2
7.a4 Rxf5 8.a5 Rf7 9.a6 Ra7 10.Bg2 Kg8
11.Kh2 Kf7 12.Kg3 Ke7 (1.812.421.826) 1042
TB:2.317


23/51 41:16 +0.63 1...Qh4 2.Kg2 Nxf2 3.a4 Ne4 4.Bf4 Rd5
5.f6 Rxf6 6.Qxe4 Rdf5 7.Qd3 Qxf4
8.Kh1 Qe5 9.Bg2 Qxb2 10.Re1 Rf2
11.a5 Rf8 12.a6 Rxc2 (2.599.839.641) 1049
TB:2.377


24/49 68:07 +0.66 1...Qh4 2.Kg2 Nxf2 3.a4 Rc8 4.c3 Ne4
5.Bf4 Rxa1 6.Qxe4 Ra2 7.Qb7 Rd8
8.Qb4 Rxb2+ 9.Qxb2 Qxf4 10.Qb5 Rf8
11.Bd3 Rb8 12.Qa6 Rb2+ 13.Be2 (4.347.579.484) 1063
TB:2.544


25/44 116:44 +0.72 1...Qh4 2.Kg2 Nxf2 3.a4 Rc8 4.c3 Ne4
5.Bf4 Rxa1 6.Qxe4 Ra2 7.Qb7 Rf8
8.Qb4 Qd8 9.Bd3 Rxb2+ 10.Qxb2 Qxd3
11.Qb4 Re8 12.Bg3 Qd5+ 13.Kg1 Qxf5 (7.510.915.306) 1072 TB:3.095


25/58 290:43 +0.87 1...Re1 2.Kg2 Ng5 3.Qc6 Nf7 4.b4 Ne5
5.Qc3 Qb7+ 6.f3 Nxf3 7.Qxf3 Qxf3+
8.Kxf3 Rxf5+ 9.Bf4 Rxa1 10.Bd3 Rf8
11.Kg3 Rg1+ 12.Kh2 Rxf4 13.Kxg1 Rxb4 (18.714.884.263) 1072 TB:9.183
Debugging is twice as hard as writing the code in the first
place. Therefore, if you write the code as cleverly as possible, you
are, by definition, not smart enough to debug it.
-- Brian W. Kernighan
Vinvin
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Re: interesting sac

Post by Vinvin »

jdart wrote:I think Glaurung is right - Qh4 first with the followup Nxf2 wins.
2 best moves after 1 hour (amd 4200+)


Analysis by HIARCS 12 MP:

1. -+ (-1.49): 1...Cxf2 2.Rxf2 Dc5+ 3.Rg2 Dxc2+ 4.Rg1 Txc1 5.Txc1 Dxc1 6.b3 Da1 7.Dg2 Db1
2. µ (-1.03): 1...Dh4 2.Rg2 Cxf2 3.a4 Cxh3 4.Dxd1 Txf5 5.De2 Tf2+ 6.Dxf2 Dxf2+ 7.Rxh3 Dxf1+ 8.Rg3 De1+ 9.Rf3 Dd1+ 10.Re3 Dxc2 11.a5 Dc5+ 12.Rf3 Dd5+ 13.Rf2 Dd4+ 14.Rg2 De4+ 15.Rf2
Tony Thomas

Re: interesting sac

Post by Tony Thomas »

From what I know Xyclops is still a private engine, another engine from the same author was released few days ago. If I had to take a guess, Xyclops is stronger than Arasan considering that it is running on a single processor. I played few games against it using Romi, and Romi was brutally defeated, so far not even one draw. On the other hand, Romi is able to win/draw Arasan once in a while..
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Dr.Wael Deeb
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Re: interesting sac

Post by Dr.Wael Deeb »

Tony Thomas wrote:From what I know Xyclops is still a private engine, another engine from the same author was released few days ago. If I had to take a guess, Xyclops is stronger than Arasan considering that it is running on a single processor. I played few games against it using Romi, and Romi was brutally defeated, so far not even one draw. On the other hand, Romi is able to win/draw Arasan once in a while..
What is the other engine from the same author that was released a few days ago Tony :?:
_No one can hit as hard as life.But it ain’t about how hard you can hit.It’s about how hard you can get hit and keep moving forward.How much you can take and keep moving forward….