Knight sac

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David Dahlem
Posts: 900
Joined: Wed Mar 08, 2006 9:06 pm

Knight sac

Post by David Dahlem »

Rybka 3 takes 8 minutes to find Nxf7+ on my machine. Komodo doesn't find it after 10 minutes. Stockfish 1.6.3s finds it easily.

[d]rn1k3r/pp3ppp/4pn2/4NP2/PbB5/2p2P2/1P4PP/R1B1K2R w KQ - 0 1

Stockfish 1.6.3s:

11 00:00 385.255 587.278 +0.44 Ke1e2 Kd8e7 b2xc3 Bb4d6 Bc1a3 Bd6xa3 Ra1xa3 Nb8c6 Ne5xc6+ b7xc6 f5xe6 f7xe6 Rh1b1 Ra8b8 Ra3b3 Rb8xb3 Rb1xb3 Ke7d6
11+ 00:01 497.270 649.177 +0.88 Ne5xf7+ Kd8e7 b2xc3 Bb4xc3+ Ke1e2 Ke7xf7 f5xe6+ Kf7e7 Bc1a3+ Ke7d8 Ra1b1 Kd8c7 Rh1c1
12 00:01 1.061.874 772.272 +1.41 Ne5xf7+ Kd8e7 b2xc3 Bb4xc3+ Ke1e2 Ke7xf7 f5xe6+ Kf7e7 Bc1a3+ Ke7d8 Ra1b1 Nb8c6 Rh1c1 Bc3e5 Rb1xb7 Rh8e8 Rc1d1+ Kd8c8 Rb7d7
13 00:02 1.916.228 834.230 +1.21 Ne5xf7+ Kd8e7 b2xc3 Bb4xc3+ Ke1e2 Ke7xf7 f5xe6+ Kf7e8 Ra1b1 Nb8c6 Rb1xb7 a7a6 Bc1a3 Nc6a5 Rb7e7+ Ke8d8 Rh1d1+ Kd8c8 Bc4a2 g7g5
14 00:04 3.600.302 882.859 +1.61 Ne5xf7+ Kd8e7 b2xc3 Bb4xc3+ Ke1e2 Ke7xf7 f5xe6+ Kf7e8 Ra1b1 Nb8c6 Rb1xb7 a7a6 Rb7xg7 Nc6e5 Bc4a2 Ra8c8 Bc1a3 Bc3d4 Rh1d1 Rc8c2+ Rd1d2 Rc2xd2+ Ke2xd2 Rh8g8 Rg7xg8+ Nf6xg8 Ba2d5
15 00:06 5.625.570 913.835 +1.49 Ne5xf7+ Kd8e7 b2xc3 Bb4xc3+ Ke1e2 Ke7xf7 f5xe6+ Kf7e8 Ra1b1 Nb8c6 Rb1xb7 a7a6 Rb7xg7 Nc6e5 Bc4a2 Ra8c8 Bc1a3 Ne5g6 g2g3 Bc3e5 Ba2b1 Nf6e4 Rg7d7 Ne4c3+ Ke2f2 Nc3xa4
16- 00:12 11.852.768 928.463 +0.84 Ne5xf7+ Kd8e7 b2xc3 Bb4xc3+ Ke1e2 Ke7xf7 f5xe6+ Kf7g6 Bc4d3+ Kg6h5 Ra1b1 Nb8c6 Rb1b5+ Bc3e5 Bc1b2 Rh8e8 Bd3c4 a7a6 Rb5c5 b7b6 g2g4+ Kh5h4 Rc5xe5 Nc6xe5 Bb2xe5 Ra8d8
17 00:21 20.178.065 930.379 +1.05 Ne5xf7+ Kd8e7 b2xc3 Bb4xc3+ Ke1e2 Ke7xf7 f5xe6+ Kf7g6 Bc4d3+ Kg6h5 Ra1b1 Nb8c6 h2h4 Ra8e8 Rb1b5+ Bc3e5 Bc1e3 b7b6 Bd3f5 Nc6d4+ Be3xd4 Be5xd4 g2g4+ Nf6xg4 f3xg4+ Kh5h6 Rb5d5 Bd4c5 g4g5+ Kh6h5 Ke2f3
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Togga

Re: Knight sac

Post by Togga »

where to download Stockfish 1.6.3s ?
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User avatar
David Dahlem
Posts: 900
Joined: Wed Mar 08, 2006 9:06 pm

Re: Knight sac

Post by David Dahlem »

Togga wrote:where to download Stockfish 1.6.3s ?
It's a special (smooth scaling) build by Dann Corbitt.

http://cap.connx.com/chess-engines/new- ... _1.6.3b.7z
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zullil
Posts: 6442
Joined: Tue Jan 09, 2007 12:31 am
Location: PA USA
Full name: Louis Zulli

Re: Knight sac

Post by zullil »

David Dahlem wrote:Rybka 3 takes 8 minutes to find Nxf7+ on my machine. Komodo doesn't find it after 10 minutes. Stockfish 1.6.3s finds it easily.

[d]rn1k3r/pp3ppp/4pn2/4NP2/PbB5/2p2P2/1P4PP/R1B1K2R w KQ - 0 1
Crafty-23.1 (8 threads) does well:

Code: Select all

Crafty v23.1 (8 cpus)

White(1): setboard rn1k3r/pp3ppp/4pn2/4NP2/PbB5/2p2P2/1P4PP/R1B1K2R w KQ - 0 1
White(1): hash 2048M
hash table memory = 2048M bytes.
White(1): st 300
search time set to 300.00.
White(1): display stats
display statistics at end of each search.
White(1): display

       +---+---+---+---+---+---+---+---+
    8  |<R>|<N>|   |<K>|   | . |   |<R>|
       +---+---+---+---+---+---+---+---+
    7  |<P>|<P>| . |   | . |<P>|<P>|<P>|
       +---+---+---+---+---+---+---+---+
    6  |   | . |   | . |<P>|<N>|   | . |
       +---+---+---+---+---+---+---+---+
    5  | . |   | . |   |-N-|-P-| . |   |
       +---+---+---+---+---+---+---+---+
    4  |-P-|<B>|-B-| . |   | . |   | . |
       +---+---+---+---+---+---+---+---+
    3  | . |   |<P>|   | . |-P-| . |   |
       +---+---+---+---+---+---+---+---+
    2  |   |-P-|   | . |   | . |-P-|-P-|
       +---+---+---+---+---+---+---+---+
    1  |-R-|   |-B-|   |-K-|   | . |-R-|
       +---+---+---+---+---+---+---+---+
         a   b   c   d   e   f   g   h

White(1): go
              time limit 5:00 (+0.00) (5:00)
              depth   time  score   variation (1)
starting thread 1
starting thread 2
starting thread 3
starting thread 4
starting thread 5
starting thread 6
starting thread 7
                8     0.04   0.27   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Bd4 Nc6 5. Nxc6+ bxc6
                8     0.06   0.47   1. O-O Ke7 2. bxc3 Bxc3 3. Ba3+ Ke8
                                    4. fxe6 fxe6 5. Bb5+ Nc6
                8->   0.06   0.47   1. O-O Ke7 2. bxc3 Bxc3 3. Ba3+ Ke8
                                    4. fxe6 fxe6 5. Bb5+ Nc6
                9     0.07   0.25   1. O-O Ke7 2. fxe6 fxe6 3. Nd3 cxb2
                                    4. Bxb2 Nc6 5. Nf4 Bc5+ 6. Kh1
                9->   0.08   0.25   1. O-O Ke7 2. fxe6 fxe6 3. Nd3 cxb2
                                    4. Bxb2 Nc6 5. Nf4 Bc5+ 6. Kh1 (s=2)
               10     0.11   0.37   1. O-O Ke7 2. fxe6 fxe6 3. Nd3 cxb2
                                    4. Bxb2 Nc6 5. Rfb1 Nh5 6. Nxb4 Nxb4
               10->   0.13   0.37   1. O-O Ke7 2. fxe6 fxe6 3. Nd3 cxb2
                                    4. Bxb2 Nc6 5. Rfb1 Nh5 6. Nxb4 Nxb4
               11     0.18   0.17   1. O-O Ke7 2. bxc3 Bxc3 3. Ba3+ Ke8
                                    4. Bb5+ Nbd7 5. Nxd7 Bd4+ 6. Kh1 Nxd7
                                    7. Rad1 e5
               11     0.39   0.39   1. Ke2 Ke7 2. bxc3 Bd6 3. Ba3 Bxa3
                                    4. Rxa3 Nc6 5. Nxc6+ bxc6 6. fxe6 fxe6
               11->   0.39   0.39   1. Ke2 Ke7 2. bxc3 Bd6 3. Ba3 Bxa3
                                    4. Rxa3 Nc6 5. Nxc6+ bxc6 6. fxe6 fxe6
                                    (s=2)
               12     0.50   0.42   1. Ke2 Ke7 2. bxc3 Bxc3 3. Ba3+ Ke8
                                    4. fxe6 fxe6 5. Bb5+ Nbd7 6. Nxd7 Nxd7
                                    7. Rad1 Rd8
               12->   0.61   0.42   1. Ke2 Ke7 2. bxc3 Bxc3 3. Ba3+ Ke8
                                    4. fxe6 fxe6 5. Bb5+ Nbd7 6. Nxd7 Nxd7
                                    7. Rad1 Rd8
               13     0.98   0.35   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Rhd1 Rc8 5. Rac1 Nc6 6. Rd3 Na5
                                    7. Kf2 Bc5+ 8. Kg3 Nxc4 9. Nxc4
               13->   1.22   0.35   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Rhd1 Rc8 5. Rac1 Nc6 6. Rd3 Na5
                                    7. Kf2 Bc5+ 8. Kg3 Nxc4 9. Nxc4
               14     1.59   0.44   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Rhb1 b6 5. Bd4 Ba5 6. Ra3 Nd5 7.
                                    Bxd5 exd5
               14->   1.97   0.44   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Rhb1 b6 5. Bd4 Ba5 6. Ra3 Nd5 7.
                                    Bxd5 exd5
               15     2.60   0.38   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Rhb1 b6 5. Bd4 Ba5 6. Ra3 Rc8 7.
                                    Re3 Nbd7 8. Rc1 Nxe5 9. Rxe5
               15->   3.73   0.38   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Rhb1 b6 5. Bd4 Ba5 6. Ra3 Rc8 7.
                                    Re3 Nbd7 8. Rc1 Nxe5 9. Rxe5 (s=2)
               16     4.97   0.26   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Rhb1 Rc8 5. Bd4 a5 6. Rc1 Nc6 7.
                                    Nxc6+ bxc6 8. Rab1 c5 9. Be5
               16->   7.95   0.26   1. Ke2 cxb2 2. Bxb2 Ke7 3. fxe6 fxe6
                                    4. Rhb1 Rc8 5. Bd4 a5 6. Rc1 Nc6 7.
                                    Nxc6+ bxc6 8. Rab1 c5 9. Be5 (s=3)
               17    24.22   0.31   1. Ke2 Ke8 2. Nd3 Nc6 3. Nxb4 Nxb4
                                    4. bxc3 Nbd5 5. Bxd5 exd5 6. Rb1 b6
                                    7. Bg5 Kd7 8. Bxf6 Rhe8+ 9. Kd3 gxf6
                                    (s=2)
               17    33.63     +1   1. Nxf7+!                         
               17    35.62   0.86   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Ne5 8. Bb3 Nc6 9. Ba2 Rd8 10.
                                    Rd1 Rxd1 11. Kxd1
               17->  37.60   0.86   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Ne5 8. Bb3 Nc6 9. Ba2 Rd8 10.
                                    Rd1 Rxd1 11. Kxd1 (s=3)
               18    41.67   0.82   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Ne5 8. Ba2 Rd8 9. Rd1 Rxd1
                                    10. Kxd1 Rg8 11. Rxg8+ Nxg8 (s=2)
               18->  47.68   0.82   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Ne5 8. Ba2 Rd8 9. Rd1 Rxd1
                                    10. Kxd1 Rg8 11. Rxg8+ Nxg8
               19    58.68   0.86   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Ne5 8. Ba2 Rd8 9. Rd1 Rxd1
                                    10. Kxd1 Nd3 11. Bd2 Ne4
               19->   1:11   0.86   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Ne5 8. Ba2 Rd8 9. Rd1 Rxd1
                                    10. Kxd1 Nd3 11. Bd2 Ne4
               20     1:34   0.86   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Nd4+ 8. Kd3 Nf5 9. Rb7 Be5
                                    10. f4 Ng4 11. Re1 Nd6 12. Rd7 Nf2+
                                    13. Ke3 Nxc4+ 14. Kxf2
               20->   2:00   0.86   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Nd4+ 8. Kd3 Nf5 9. Rb7 Be5
                                    10. f4 Ng4 11. Re1 Nd6 12. Rd7 Nf2+
                                    13. Ke3 Nxc4+ 14. Kxf2
               21     2:57   0.87   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Ne5 8. Ba2 Rd8 9. Rd1 Rxd1
                                    10. Kxd1 Nd3 11. Bd2 <HT>
               21->   4:00   0.87   1. Nxf7+ Ke7 2. bxc3 Bxc3+ 3. Ke2 Kxf7
                                    4. fxe6+ Ke8 5. Rb1 Nc6 6. Rxb7 a6
                                    7. Rxg7 Ne5 8. Ba2 Rd8 9. Rd1 Rxd1
                                    10. Kxd1 Nd3 11. Bd2 <HT>
              time=5:00  mat=-1  n=7254554899  fh=92%  nps=24.2M      
              extensions=292.1M qchecks=354.1M reduced=684.6M pruned=2744.5M
              predicted=0  evals=3110.9M  50move=0  EGTBprobes=0  hits=0
              SMP->  splits=735847  aborts=64517  data=62/1024  elap=5:00
terminating SMP processes.
White(1): Nxf7+
              time used:   5:00
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User avatar
David Dahlem
Posts: 900
Joined: Wed Mar 08, 2006 9:06 pm

Re: Knight sac

Post by David Dahlem »

zullil wrote:
Crafty-23.1 (8 threads) does well:
Stockfish 1.6.3s was using 1 thread. :lol:
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yanquis1972
Posts: 1766
Joined: Wed Jun 03, 2009 12:14 am

Re: Knight sac

Post by yanquis1972 »

R3 Human --

[+1.38] d=16 1.Nxf7 (0:00:40) 18092kN
[+1.18] d=15 1.Nxf7 Ke8 2.bxc3 Bxc3 3.Ke2 Kxf7 4.fxe6 Ke8 (0:00:27) 12273kN
[+1.14] d=14 1.Nxf7 Ke8 2.bxc3 Bxc3 3.Ke2 Bxa1 4.Nxh8 exf5 5.Nf7 Nc6 6.Nd6 Kd7 7.Nxf5 Ne8 8.Be3 Be5 9.f4 Bf6 10.Rd1 (0:00:18) 8481kN
[+1.14] d=13 1.Nxf7 Ke8 2.bxc3 Bxc3 3.Ke2 Bxa1 4.Nxh8 exf5 5.Nf7 Nc6 6.Nd6 Kd7 7.Nxf5 Ne8 8.Be3 Be5 9.f4 Bf6 10.Rd1 (0:00:17) 7993kN
[+0.76] d=13 1.Nxf7 (0:00:13) 6179kN
[+0.56] d=13 1.Nxf7 (0:00:08) 3998kN
[+0.38] d=13 1.O–O cxb2 2.Bxb2 Ke7 3.fxe6 fxe6 4.Nd3 Rc8 5.Rac1 Bd2 6.Ba3 Ke8 7.Bxe6 Rxc1 8.Nxc1 Nc6 9.Nb3 Rd8 10.Nxd2 Rxd2 11.Rb1 Re2 (0:00:07) 3563kN
[+0.36] d=12 1.O–O cxb2 2.Bxb2 Ke7 3.fxe6 fxe6 4.Nd3 Rc8 5.Ba2 Nc6 6.Rab1 a5 7.Nf4 Nd8 8.Rfd1 Rc2 (0:00:06) 2867kN
[+0.58] d=12 1.O–O (0:00:01) 783kN
[+0.35] d=12 1.Ke2 Ke7 2.bxc3 Bd6 3.Ba3 Bxa3 4.Rxa3 Nc6 5.Nxc6 bxc6 6.fxe6 fxe6 7.Rb1 Rhb8 8.Rab3 Rxb3 9.Rxb3 Rd8 10.a5 (0:00:01) 461kN
[+0.38] d=11 1.Ke2 Ke7 2.bxc3 Bd6 3.Ba3 Bxa3 4.Rxa3 Nc6 5.Nxc6 bxc6 6.fxe6 fxe6 7.Rb1 Rhb8 8.Rab3 (0:00:00) 322kN
[+0.41] d=10 1.Ke2 Ke7 2.bxc3 Bd6 3.Ba3 Bxa3 4.Rxa3 Nc6 5.Nxc6 bxc6 6.fxe6 fxe6 7.Rb3 Rhb8 (0:00:00) 258kN
[+0.36] d=9 1.Ke2 Ke7 2.bxc3 Bd6 3.Ba3 Bxa3 4.Rxa3 Nc6 5.Nxc6 bxc6 6.fxe6 (0:00:00) 230kN
[+0.36] d=8 1.Ke2 Ke7 2.bxc3 Bd6 3.Ba3 Bxa3 4.Rxa3 Nc6 5.Nxc6 bxc6 6.fxe6 (0:00:00) 228kN
[-0.01] d=8 1.O–O Ke7 2.fxe6 fxe6 3.bxc3 Bxc3 4.Ba3 Ke8 5.Rae1 Bxe1 6.Rxe1 Nbd7 (0:00:00) 186kN
[+0.61] d=7 1.O–O Ke7 2.fxe6 fxe6 3.bxc3 Bxc3 4.Ba3 (0:00:00) 22kN
[+0.52] d=7 1.O–O (0:00:00) 20kN
[+0.32] d=6 1.O–O Ke7 2.fxe6 (0:00:00) 19kN
[+0.69] d=5 1.O–O Rf8 (0:00:00) 8kN
[+0.70] d=5 1.O–O (0:00:00) 7kN
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rightrook
Posts: 1452
Joined: Wed Mar 08, 2006 8:45 pm

Re: Knight sac

Post by rightrook »

Hiarcs 11.2.....finds it in 4 min. 20 seconds..

Good test!

:D
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kgburcham
Posts: 2016
Joined: Sun Feb 17, 2008 4:19 pm

Re: Knight sac

Post by kgburcham »

[d] rn1k3r/pp3ppp/4pn2/4NP2/PbB5/2p2P2/1P4PP/R1B1K2R w KQ -

Rybka 3

17.05 1:36 +0.68++ 1.Nxf7+ (30.877.351) 329
17.01 1:52 +0.88++ 1.Nxf7+ (34.904.118) 316
17.01 3:20 +1.28++ 1.Nxf7+ (61.512.350) 314
17.01 5:02 +1.41 1.Nxf7+ Ke8 2.bxc3 Bxc3+ 3.Ke2 Bxa1 4.fxe6 Rg8 5.Nd6+ Kd8 6.Bf4 (90.836.906) 307
18.01 8:04 +1.61++ 1.Nxf7+ (144.618.777) 305
18.01 11:04 +1.71 1.Nxf7+ Ke8 2.bxc3 Bxc3+ 3.Ke2 Kxf7 4.fxe6+ (194.279.344) 299
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rlsuth
Posts: 322
Joined: Wed Mar 08, 2006 9:37 pm

Re: Knight sac

Post by rlsuth »

After 37 minutes, Nimzo 8 found it.

:)
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yanquis1972
Posts: 1766
Joined: Wed Jun 03, 2009 12:14 am

Re: Knight sac

Post by yanquis1972 »

i was just thinking about nimzo yesterday. are you a fan? i never had a copy or saw a game, but i remember its reputation was that of a primitive, brute force engine...dull, no special knowledge, but searched deep enough to be mentioned with the top dogs, i guess. is that more or less accurate?
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