1.. Rxb2! is an obvious win for back. Even none masters can spot it.

Shredder 10 and Deep Junior 10 solved it in around 1 minute!

But Rybka 2.3.2a didn't see it even after 1hour until I gave up.

Maybe I just wrongly configured Rybka in my PIV 2.6mhz 1Gig RAM. Can you try it in your system??

SOLUTION 1..Rxb2!

Shredder 10 and Deep Junior 10 solved it in around 1 minute!

But Rybka 2.3.2a didn't see it even after 1hour until I gave up.

Maybe I just wrongly configured Rybka in my PIV 2.6mhz 1Gig RAM. Can you try it in your system??

8/pR4pk/1b6/2p5/N1p5/8/PP1r2PP/6K1 b - - 0 2

SOLUTION 1..Rxb2!

Hiarcs finds it in about a half minute (3200+ sp). Fritz, Rybka, Shredder, and Toga do not find it within 5 minutes (I didn't wait around longer).

Check. WinFinder spots it in 20 seconds. And Naum 2.0 (!) finds it in 30 seconds. Interesting.

Check. WinFinder spots it in 20 seconds. And Naum 2.0 (!) finds it in 30 seconds. Interesting.

Some results on my computer with a similar CPU:

Rybka 2.3.2a - 90 seconds

Ktulu 8 - 60 seconds

Zap Zanzibar - 60 seconds

Shredder 10.1 - 40 seconds

Junior 10 - 40 seconds

Naum 2.0 - 30 seconds

Alaric 7.07 - 20 seconds

Glaurung 2e5 - 15 seconds

Yace Paderborn - 10 seconds

Rybka Winfinder - 4 seconds

Chess Tiger 2007 - 4 seconds

Spike 1.2 - 2 seconds!!

Rybka 2.3.2a - 90 seconds

Ktulu 8 - 60 seconds

Zap Zanzibar - 60 seconds

Shredder 10.1 - 40 seconds

Junior 10 - 40 seconds

Naum 2.0 - 30 seconds

Alaric 7.07 - 20 seconds

Glaurung 2e5 - 15 seconds

Yace Paderborn - 10 seconds

Rybka Winfinder - 4 seconds

Chess Tiger 2007 - 4 seconds

Spike 1.2 - 2 seconds!!

How about Rybka 2.3.2a on your system? Did it find the solution too? How long?

thanx..

thanx..

Hmm, yes Rybka 2.3.2a found it in 90 seconds, guess I was just delusional the first time around. :)

Looks like 2 issues; one issue is, did the engine "find" the solution?, and the other is "how long did it take?".

Looks like the first point had to do with Rybka not finding the solution in a reasonable amount of time. Chessmaster 9000 did find that 1....Rxb2 was the turning point for Black. It took 8 min 40 sec, but being connected to the Internet at the same time slows it down a bit. Some settings on Chessmaster could have been tweaked to maybe get a faster solution, but I am satisfied that it at least got the answer on a vintage 2002 program (lol).

Looks like the first point had to do with Rybka not finding the solution in a reasonable amount of time. Chessmaster 9000 did find that 1....Rxb2 was the turning point for Black. It took 8 min 40 sec, but being connected to the Internet at the same time slows it down a bit. Some settings on Chessmaster could have been tweaked to maybe get a faster solution, but I am satisfied that it at least got the answer on a vintage 2002 program (lol).

>Fritz, Rybka, Shredder, and Toga

What versions of these and in what hardware?

My Fritz 8.00.23 finds this in 36 seconds in a AMD 3800+ 2.2 GHz.

Also Shredder 10 finds this in 37 seconds.

Also Toga II 1.3x4 finds this in 3:57 minutes

Rybka default has indeed problems with this.....

Hello, how much memory did you use for hashtables? With 1 Gig of RAM, 512 Mb should be OK.

I got this result :

CPU0: GenuineIntel x86 Family 6 Model 14 Stepping 8 1828 MHz

CPU1: GenuineIntel x86 Family 6 Model 14 Stepping 8 1828 MHz

Engine: Rybka 2.3.2a 32-bit (512 MB)

by Vasik Rajlich

UCI_AnalyseMode set to true

5.00 0:00 +0.38 1...c3 2.bxc3 (840) 26

5.00 0:00 +0.24 1...Bd8 2.h3 (2.224) 35

6.00 0:00 +0.10 1...Bd8 2.h3 Bf6 (3.476) 45

7.00 0:00 +0.07 1...Bd8 2.g3 Bf6 3.h4 (7.667) 55

8.00 0:00 +0.02 1...Bd8 2.g3 Bf6 3.h3 Kg6 (14.944) 60

9.00 0:00 -0.04 1...Bd8 2.g3 Bf6 3.h3 Kg6 4.Kf1 (24.220) 65

10.00 0:00 -0.02 1...Bd8 2.g3 Bf6 3.h3 Kg6 4.Kf1 Kf5 (36.972) 71

11.00 0:00 -0.06 1...Bd8 2.g3 Bf6 3.h3 Kg6 4.Kf1 Kf5 5.Rb5 (63.446) 75

12.00 0:02 -0.14 1...Bd8 2.Kf1 Bf6 3.h4 Kg6 4.g3 Be5 5.g4 Rh2 (171.557) 75

13.01 0:03 -0.19 1...Bd8 2.Kf1 Bf6 3.h3 Kg6 4.Kg1 Be5 5.Kf1 Bd4 6.g4 Rf2+ 7.Ke1 (271.683) 78

14.01 0:04 -0.19 1...Bd8 2.Kf1 Bf6 3.h3 Kg6 4.Kg1 Be5 5.Kf1 Bd4 6.g4 Rf2+ 7.Ke1 Rh2 (387.352) 81

15.01 0:08 -0.16 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Ne4 Be5 7.Nd2 Bxh2 8.Nxc4 (659.370) 81

16.01 0:11 -0.11 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Ne4 Be5 7.Nd2 Bxh2 8.Nxc4 (943.574) 81

17.01 0:17 -0.12 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Ne4 Be5 7.Nd2 Bxh2 8.Nxc4 (1.416.643) 83

18.01 0:26 -0.12 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Ne4 Be5 7.Nd2 Bxh2 8.Nxc4 (2.158.694) 83

19.01 0:48 -0.04 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Nb7 Bc3 7.Nd6 Be5 8.Nxc4 (3.731.796) 79

20.01 1:24 -0.03 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Nb7 Bc3 7.Nd6 Be5 8.Nxc4 (6.243.738) 75 TB:2

20.04 2:22 -2.54 1...Rxb2 2.Nxb2 c3 3.Rxb6 c4 4.Rb4 a5 5.Nd3 cxd3 6.Rh4+ Kg8 (11.456.865) 82 TB:10

20.01 5:52 -2.71 1...Rxb2 2.Re7 Rxa2 3.Nc3 Ra3 4.Nd5 c3 5.Re2 Ra1+ 6.Kf2 Rd1 7.Nf4 c4+ 8.Kf3 (31.225.860) 90 TB:17

21.01 6:07 -2.77 1...Rxb2 2.Re7 Rxa2 3.Nc3 Ra3 4.Nd5 c3 5.Re2 Ra1+ 6.Kf2 Rd1 7.Nf4 c4+ 8.Kf3 (32.597.841) 90 TB:18

I have sereral 6-men tablebases, they are useful to find 1...Rxb2 faster. It took 4 min 32 s to find 1...Rxb2 without my 6-men tablebases.

One hour without finding 1..Rxb2 seems strange to me.

Best regards,

Sylvain

I got this result :

CPU0: GenuineIntel x86 Family 6 Model 14 Stepping 8 1828 MHz

CPU1: GenuineIntel x86 Family 6 Model 14 Stepping 8 1828 MHz

Engine: Rybka 2.3.2a 32-bit (512 MB)

by Vasik Rajlich

UCI_AnalyseMode set to true

5.00 0:00 +0.38 1...c3 2.bxc3 (840) 26

5.00 0:00 +0.24 1...Bd8 2.h3 (2.224) 35

6.00 0:00 +0.10 1...Bd8 2.h3 Bf6 (3.476) 45

7.00 0:00 +0.07 1...Bd8 2.g3 Bf6 3.h4 (7.667) 55

8.00 0:00 +0.02 1...Bd8 2.g3 Bf6 3.h3 Kg6 (14.944) 60

9.00 0:00 -0.04 1...Bd8 2.g3 Bf6 3.h3 Kg6 4.Kf1 (24.220) 65

10.00 0:00 -0.02 1...Bd8 2.g3 Bf6 3.h3 Kg6 4.Kf1 Kf5 (36.972) 71

11.00 0:00 -0.06 1...Bd8 2.g3 Bf6 3.h3 Kg6 4.Kf1 Kf5 5.Rb5 (63.446) 75

12.00 0:02 -0.14 1...Bd8 2.Kf1 Bf6 3.h4 Kg6 4.g3 Be5 5.g4 Rh2 (171.557) 75

13.01 0:03 -0.19 1...Bd8 2.Kf1 Bf6 3.h3 Kg6 4.Kg1 Be5 5.Kf1 Bd4 6.g4 Rf2+ 7.Ke1 (271.683) 78

14.01 0:04 -0.19 1...Bd8 2.Kf1 Bf6 3.h3 Kg6 4.Kg1 Be5 5.Kf1 Bd4 6.g4 Rf2+ 7.Ke1 Rh2 (387.352) 81

15.01 0:08 -0.16 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Ne4 Be5 7.Nd2 Bxh2 8.Nxc4 (659.370) 81

16.01 0:11 -0.11 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Ne4 Be5 7.Nd2 Bxh2 8.Nxc4 (943.574) 81

17.01 0:17 -0.12 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Ne4 Be5 7.Nd2 Bxh2 8.Nxc4 (1.416.643) 83

18.01 0:26 -0.12 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Ne4 Be5 7.Nd2 Bxh2 8.Nxc4 (2.158.694) 83

19.01 0:48 -0.04 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Nb7 Bc3 7.Nd6 Be5 8.Nxc4 (3.731.796) 79

20.01 1:24 -0.03 1...Bd8 2.Kf1 Bf6 3.Nxc5 Rxb2 4.Rxb2 Bxb2 5.Ke2 Kg6 6.Nb7 Bc3 7.Nd6 Be5 8.Nxc4 (6.243.738) 75 TB:2

20.04 2:22 -2.54 1...Rxb2 2.Nxb2 c3 3.Rxb6 c4 4.Rb4 a5 5.Nd3 cxd3 6.Rh4+ Kg8 (11.456.865) 82 TB:10

20.01 5:52 -2.71 1...Rxb2 2.Re7 Rxa2 3.Nc3 Ra3 4.Nd5 c3 5.Re2 Ra1+ 6.Kf2 Rd1 7.Nf4 c4+ 8.Kf3 (31.225.860) 90 TB:17

21.01 6:07 -2.77 1...Rxb2 2.Re7 Rxa2 3.Nc3 Ra3 4.Nd5 c3 5.Re2 Ra1+ 6.Kf2 Rd1 7.Nf4 c4+ 8.Kf3 (32.597.841) 90 TB:18

I have sereral 6-men tablebases, they are useful to find 1...Rxb2 faster. It took 4 min 32 s to find 1...Rxb2 without my 6-men tablebases.

One hour without finding 1..Rxb2 seems strange to me.

Best regards,

Sylvain

Thanx man! It's probably because I forgot to install any tablebase :)

But it's interesting that Shredder & Junior 10 solved it without tablebase...

But it's interesting that Shredder & Junior 10 solved it without tablebase...

In fact, with my computer and no tablebase access, Rybka 2.3.2a found the solution in 4 min 32 s.

But it is clearly a position where Rybka is not brilliant. Even my program Capture is faster than Rybka!

Best regards,

Sylvain

But it is clearly a position where Rybka is not brilliant. Even my program Capture is faster than Rybka!

Best regards,

Sylvain

can you specifically name the masters that can't find this?

He said that also players which are not masters can find this. And that's true since this combination is really well known :)

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